JingleRtpConnection.java

   1package eu.siacs.conversations.xmpp.jingle;
   2
   3import android.os.SystemClock;
   4import android.util.Log;
   5
   6import androidx.annotation.NonNull;
   7import androidx.annotation.Nullable;
   8
   9import com.google.common.base.Optional;
  10import com.google.common.base.Preconditions;
  11import com.google.common.base.Strings;
  12import com.google.common.base.Throwables;
  13import com.google.common.collect.Collections2;
  14import com.google.common.collect.ImmutableList;
  15import com.google.common.collect.ImmutableMap;
  16import com.google.common.collect.Sets;
  17import com.google.common.primitives.Ints;
  18import com.google.common.util.concurrent.FutureCallback;
  19import com.google.common.util.concurrent.Futures;
  20import com.google.common.util.concurrent.ListenableFuture;
  21import com.google.common.util.concurrent.MoreExecutors;
  22
  23import org.webrtc.EglBase;
  24import org.webrtc.IceCandidate;
  25import org.webrtc.PeerConnection;
  26import org.webrtc.VideoTrack;
  27
  28import java.util.ArrayDeque;
  29import java.util.Arrays;
  30import java.util.Collection;
  31import java.util.Collections;
  32import java.util.List;
  33import java.util.Map;
  34import java.util.Set;
  35import java.util.concurrent.ScheduledFuture;
  36import java.util.concurrent.TimeUnit;
  37
  38import eu.siacs.conversations.Config;
  39import eu.siacs.conversations.crypto.axolotl.AxolotlService;
  40import eu.siacs.conversations.crypto.axolotl.CryptoFailedException;
  41import eu.siacs.conversations.crypto.axolotl.FingerprintStatus;
  42import eu.siacs.conversations.entities.Account;
  43import eu.siacs.conversations.entities.Conversation;
  44import eu.siacs.conversations.entities.Conversational;
  45import eu.siacs.conversations.entities.Message;
  46import eu.siacs.conversations.entities.RtpSessionStatus;
  47import eu.siacs.conversations.services.AppRTCAudioManager;
  48import eu.siacs.conversations.utils.IP;
  49import eu.siacs.conversations.xml.Element;
  50import eu.siacs.conversations.xml.Namespace;
  51import eu.siacs.conversations.xmpp.Jid;
  52import eu.siacs.conversations.xmpp.jingle.stanzas.Group;
  53import eu.siacs.conversations.xmpp.jingle.stanzas.IceUdpTransportInfo;
  54import eu.siacs.conversations.xmpp.jingle.stanzas.JinglePacket;
  55import eu.siacs.conversations.xmpp.jingle.stanzas.Proceed;
  56import eu.siacs.conversations.xmpp.jingle.stanzas.Propose;
  57import eu.siacs.conversations.xmpp.jingle.stanzas.Reason;
  58import eu.siacs.conversations.xmpp.jingle.stanzas.RtpDescription;
  59import eu.siacs.conversations.xmpp.stanzas.IqPacket;
  60import eu.siacs.conversations.xmpp.stanzas.MessagePacket;
  61
  62public class JingleRtpConnection extends AbstractJingleConnection implements WebRTCWrapper.EventCallback {
  63
  64    public static final List<State> STATES_SHOWING_ONGOING_CALL = Arrays.asList(
  65            State.PROCEED,
  66            State.SESSION_INITIALIZED_PRE_APPROVED,
  67            State.SESSION_ACCEPTED
  68    );
  69    private static final long BUSY_TIME_OUT = 30;
  70    private static final List<State> TERMINATED = Arrays.asList(
  71            State.ACCEPTED,
  72            State.REJECTED,
  73            State.REJECTED_RACED,
  74            State.RETRACTED,
  75            State.RETRACTED_RACED,
  76            State.TERMINATED_SUCCESS,
  77            State.TERMINATED_DECLINED_OR_BUSY,
  78            State.TERMINATED_CONNECTIVITY_ERROR,
  79            State.TERMINATED_CANCEL_OR_TIMEOUT,
  80            State.TERMINATED_APPLICATION_FAILURE,
  81            State.TERMINATED_SECURITY_ERROR
  82    );
  83
  84    private static final Map<State, Collection<State>> VALID_TRANSITIONS;
  85
  86    static {
  87        final ImmutableMap.Builder<State, Collection<State>> transitionBuilder = new ImmutableMap.Builder<>();
  88        transitionBuilder.put(State.NULL, ImmutableList.of(
  89                State.PROPOSED,
  90                State.SESSION_INITIALIZED,
  91                State.TERMINATED_APPLICATION_FAILURE,
  92                State.TERMINATED_SECURITY_ERROR
  93        ));
  94        transitionBuilder.put(State.PROPOSED, ImmutableList.of(
  95                State.ACCEPTED,
  96                State.PROCEED,
  97                State.REJECTED,
  98                State.RETRACTED,
  99                State.TERMINATED_APPLICATION_FAILURE,
 100                State.TERMINATED_SECURITY_ERROR,
 101                State.TERMINATED_CONNECTIVITY_ERROR //only used when the xmpp connection rebinds
 102        ));
 103        transitionBuilder.put(State.PROCEED, ImmutableList.of(
 104                State.REJECTED_RACED,
 105                State.RETRACTED_RACED,
 106                State.SESSION_INITIALIZED_PRE_APPROVED,
 107                State.TERMINATED_SUCCESS,
 108                State.TERMINATED_APPLICATION_FAILURE,
 109                State.TERMINATED_SECURITY_ERROR,
 110                State.TERMINATED_CONNECTIVITY_ERROR //at this state used for error bounces of the proceed message
 111        ));
 112        transitionBuilder.put(State.SESSION_INITIALIZED, ImmutableList.of(
 113                State.SESSION_ACCEPTED,
 114                State.TERMINATED_SUCCESS,
 115                State.TERMINATED_DECLINED_OR_BUSY,
 116                State.TERMINATED_CONNECTIVITY_ERROR,  //at this state used for IQ errors and IQ timeouts
 117                State.TERMINATED_CANCEL_OR_TIMEOUT,
 118                State.TERMINATED_APPLICATION_FAILURE,
 119                State.TERMINATED_SECURITY_ERROR
 120        ));
 121        transitionBuilder.put(State.SESSION_INITIALIZED_PRE_APPROVED, ImmutableList.of(
 122                State.SESSION_ACCEPTED,
 123                State.TERMINATED_SUCCESS,
 124                State.TERMINATED_DECLINED_OR_BUSY,
 125                State.TERMINATED_CONNECTIVITY_ERROR,  //at this state used for IQ errors and IQ timeouts
 126                State.TERMINATED_CANCEL_OR_TIMEOUT,
 127                State.TERMINATED_APPLICATION_FAILURE,
 128                State.TERMINATED_SECURITY_ERROR
 129        ));
 130        transitionBuilder.put(State.SESSION_ACCEPTED, ImmutableList.of(
 131                State.TERMINATED_SUCCESS,
 132                State.TERMINATED_DECLINED_OR_BUSY,
 133                State.TERMINATED_CONNECTIVITY_ERROR,
 134                State.TERMINATED_CANCEL_OR_TIMEOUT,
 135                State.TERMINATED_APPLICATION_FAILURE,
 136                State.TERMINATED_SECURITY_ERROR
 137        ));
 138        VALID_TRANSITIONS = transitionBuilder.build();
 139    }
 140
 141    private final WebRTCWrapper webRTCWrapper = new WebRTCWrapper(this);
 142    private final ArrayDeque<Set<Map.Entry<String, RtpContentMap.DescriptionTransport>>> pendingIceCandidates = new ArrayDeque<>();
 143    private final OmemoVerification omemoVerification = new OmemoVerification();
 144    private final Message message;
 145    private State state = State.NULL;
 146    private StateTransitionException stateTransitionException;
 147    private Set<Media> proposedMedia;
 148    private RtpContentMap initiatorRtpContentMap;
 149    private RtpContentMap responderRtpContentMap;
 150    private long rtpConnectionStarted = 0; //time of 'connected'
 151    private long rtpConnectionEnded = 0;
 152    private ScheduledFuture<?> ringingTimeoutFuture;
 153
 154    JingleRtpConnection(JingleConnectionManager jingleConnectionManager, Id id, Jid initiator) {
 155        super(jingleConnectionManager, id, initiator);
 156        final Conversation conversation = jingleConnectionManager.getXmppConnectionService().findOrCreateConversation(
 157                id.account,
 158                id.with.asBareJid(),
 159                false,
 160                false
 161        );
 162        this.message = new Message(
 163                conversation,
 164                isInitiator() ? Message.STATUS_SEND : Message.STATUS_RECEIVED,
 165                Message.TYPE_RTP_SESSION,
 166                id.sessionId
 167        );
 168    }
 169
 170    private static State reasonToState(Reason reason) {
 171        switch (reason) {
 172            case SUCCESS:
 173                return State.TERMINATED_SUCCESS;
 174            case DECLINE:
 175            case BUSY:
 176                return State.TERMINATED_DECLINED_OR_BUSY;
 177            case CANCEL:
 178            case TIMEOUT:
 179                return State.TERMINATED_CANCEL_OR_TIMEOUT;
 180            case SECURITY_ERROR:
 181                return State.TERMINATED_SECURITY_ERROR;
 182            case FAILED_APPLICATION:
 183            case UNSUPPORTED_TRANSPORTS:
 184            case UNSUPPORTED_APPLICATIONS:
 185                return State.TERMINATED_APPLICATION_FAILURE;
 186            default:
 187                return State.TERMINATED_CONNECTIVITY_ERROR;
 188        }
 189    }
 190
 191    @Override
 192    synchronized void deliverPacket(final JinglePacket jinglePacket) {
 193        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": packet delivered to JingleRtpConnection");
 194        switch (jinglePacket.getAction()) {
 195            case SESSION_INITIATE:
 196                receiveSessionInitiate(jinglePacket);
 197                break;
 198            case TRANSPORT_INFO:
 199                receiveTransportInfo(jinglePacket);
 200                break;
 201            case SESSION_ACCEPT:
 202                receiveSessionAccept(jinglePacket);
 203                break;
 204            case SESSION_TERMINATE:
 205                receiveSessionTerminate(jinglePacket);
 206                break;
 207            default:
 208                respondOk(jinglePacket);
 209                Log.d(Config.LOGTAG, String.format("%s: received unhandled jingle action %s", id.account.getJid().asBareJid(), jinglePacket.getAction()));
 210                break;
 211        }
 212    }
 213
 214    @Override
 215    synchronized void notifyRebound() {
 216        if (isTerminated()) {
 217            return;
 218        }
 219        webRTCWrapper.close();
 220        if (!isInitiator() && isInState(State.PROPOSED, State.SESSION_INITIALIZED)) {
 221            xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
 222        }
 223        if (isInState(State.SESSION_INITIALIZED, State.SESSION_INITIALIZED_PRE_APPROVED, State.SESSION_ACCEPTED)) {
 224            //we might have already changed resources (full jid) at this point; so this might not even reach the other party
 225            sendSessionTerminate(Reason.CONNECTIVITY_ERROR);
 226        } else {
 227            transitionOrThrow(State.TERMINATED_CONNECTIVITY_ERROR);
 228            finish();
 229        }
 230    }
 231
 232    private void receiveSessionTerminate(final JinglePacket jinglePacket) {
 233        respondOk(jinglePacket);
 234        final JinglePacket.ReasonWrapper wrapper = jinglePacket.getReason();
 235        final State previous = this.state;
 236        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received session terminate reason=" + wrapper.reason + "(" + Strings.nullToEmpty(wrapper.text) + ") while in state " + previous);
 237        if (TERMINATED.contains(previous)) {
 238            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": ignoring session terminate because already in " + previous);
 239            return;
 240        }
 241        webRTCWrapper.close();
 242        final State target = reasonToState(wrapper.reason);
 243        transitionOrThrow(target);
 244        writeLogMessage(target);
 245        if (previous == State.PROPOSED || previous == State.SESSION_INITIALIZED) {
 246            xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
 247        }
 248        finish();
 249    }
 250
 251    private void receiveTransportInfo(final JinglePacket jinglePacket) {
 252        //Due to the asynchronicity of processing session-init we might move from NULL|PROCEED to INITIALIZED only after transport-info has been received
 253        if (isInState(State.NULL, State.PROCEED, State.SESSION_INITIALIZED, State.SESSION_INITIALIZED_PRE_APPROVED, State.SESSION_ACCEPTED)) {
 254            respondOk(jinglePacket);
 255            final RtpContentMap contentMap;
 256            try {
 257                contentMap = RtpContentMap.of(jinglePacket);
 258            } catch (IllegalArgumentException | NullPointerException e) {
 259                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": improperly formatted contents; ignoring", e);
 260                return;
 261            }
 262            final Set<Map.Entry<String, RtpContentMap.DescriptionTransport>> candidates = contentMap.contents.entrySet();
 263            if (this.state == State.SESSION_ACCEPTED) {
 264                try {
 265                    processCandidates(candidates);
 266                } catch (final WebRTCWrapper.PeerConnectionNotInitialized e) {
 267                    Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": PeerConnection was not initialized when processing transport info. this usually indicates a race condition that can be ignored");
 268                }
 269            } else {
 270                pendingIceCandidates.push(candidates);
 271            }
 272        } else {
 273            if (isTerminated()) {
 274                respondOk(jinglePacket);
 275                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": ignoring out-of-order transport info; we where already terminated");
 276            } else {
 277                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received transport info while in state=" + this.state);
 278                terminateWithOutOfOrder(jinglePacket);
 279            }
 280        }
 281    }
 282
 283    private void processCandidates(final Set<Map.Entry<String, RtpContentMap.DescriptionTransport>> contents) {
 284        final RtpContentMap rtpContentMap = isInitiator() ? this.responderRtpContentMap : this.initiatorRtpContentMap;
 285        final Group originalGroup = rtpContentMap.group;
 286        final List<String> identificationTags = originalGroup == null ? rtpContentMap.getNames() : originalGroup.getIdentificationTags();
 287        if (identificationTags.size() == 0) {
 288            Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": no identification tags found in initial offer. we won't be able to calculate mLineIndices");
 289        }
 290        processCandidates(identificationTags, contents);
 291    }
 292
 293    private void processCandidates(final List<String> indices, final Set<Map.Entry<String, RtpContentMap.DescriptionTransport>> contents) {
 294        for (final Map.Entry<String, RtpContentMap.DescriptionTransport> content : contents) {
 295            final String ufrag = content.getValue().transport.getAttribute("ufrag");
 296            for (final IceUdpTransportInfo.Candidate candidate : content.getValue().transport.getCandidates()) {
 297                final String sdp;
 298                try {
 299                    sdp = candidate.toSdpAttribute(ufrag);
 300                } catch (IllegalArgumentException e) {
 301                    Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": ignoring invalid ICE candidate " + e.getMessage());
 302                    continue;
 303                }
 304                final String sdpMid = content.getKey();
 305                final int mLineIndex = indices.indexOf(sdpMid);
 306                if (mLineIndex < 0) {
 307                    Log.w(Config.LOGTAG, "mLineIndex not found for " + sdpMid + ". available indices " + indices);
 308                }
 309                final IceCandidate iceCandidate = new IceCandidate(sdpMid, mLineIndex, sdp);
 310                Log.d(Config.LOGTAG, "received candidate: " + iceCandidate);
 311                this.webRTCWrapper.addIceCandidate(iceCandidate);
 312            }
 313        }
 314    }
 315
 316    private ListenableFuture<RtpContentMap> receiveRtpContentMap(final JinglePacket jinglePacket, final boolean expectVerification) {
 317        final RtpContentMap receivedContentMap = RtpContentMap.of(jinglePacket);
 318        if (receivedContentMap instanceof OmemoVerifiedRtpContentMap) {
 319            final ListenableFuture<AxolotlService.OmemoVerifiedPayload<RtpContentMap>> future = id.account.getAxolotlService().decrypt((OmemoVerifiedRtpContentMap) receivedContentMap, id.with);
 320            return Futures.transform(future, omemoVerifiedPayload -> {
 321                //TODO test if an exception here triggers a correct abort
 322                omemoVerification.setOrEnsureEqual(omemoVerifiedPayload);
 323                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received verifiable DTLS fingerprint via " + omemoVerification);
 324                return omemoVerifiedPayload.getPayload();
 325            }, MoreExecutors.directExecutor());
 326        } else if (Config.REQUIRE_RTP_VERIFICATION || expectVerification) {
 327            return Futures.immediateFailedFuture(
 328                    new SecurityException("DTLS fingerprint was unexpectedly not verifiable")
 329            );
 330        } else {
 331            return Futures.immediateFuture(receivedContentMap);
 332        }
 333    }
 334
 335    private void receiveSessionInitiate(final JinglePacket jinglePacket) {
 336        if (isInitiator()) {
 337            Log.d(Config.LOGTAG, String.format("%s: received session-initiate even though we were initiating", id.account.getJid().asBareJid()));
 338            if (isTerminated()) {
 339                Log.d(Config.LOGTAG, String.format(
 340                        "%s: got a reason to terminate with out-of-order. but already in state %s",
 341                        id.account.getJid().asBareJid(),
 342                        getState()
 343                ));
 344                respondWithOutOfOrder(jinglePacket);
 345            } else {
 346                terminateWithOutOfOrder(jinglePacket);
 347            }
 348            return;
 349        }
 350        final ListenableFuture<RtpContentMap> future = receiveRtpContentMap(jinglePacket, false);
 351        Futures.addCallback(future, new FutureCallback<RtpContentMap>() {
 352            @Override
 353            public void onSuccess(@Nullable RtpContentMap rtpContentMap) {
 354                receiveSessionInitiate(jinglePacket, rtpContentMap);
 355            }
 356
 357            @Override
 358            public void onFailure(@NonNull final Throwable throwable) {
 359                respondOk(jinglePacket);
 360                sendSessionTerminate(Reason.ofThrowable(throwable), throwable.getMessage());
 361            }
 362        }, MoreExecutors.directExecutor());
 363    }
 364
 365    private void receiveSessionInitiate(final JinglePacket jinglePacket, final RtpContentMap contentMap) {
 366        try {
 367            contentMap.requireContentDescriptions();
 368            contentMap.requireDTLSFingerprint();
 369        } catch (final RuntimeException e) {
 370            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": improperly formatted contents", Throwables.getRootCause(e));
 371            respondOk(jinglePacket);
 372            sendSessionTerminate(Reason.of(e), e.getMessage());
 373            return;
 374        }
 375        Log.d(Config.LOGTAG, "processing session-init with " + contentMap.contents.size() + " contents");
 376        final State target;
 377        if (this.state == State.PROCEED) {
 378            Preconditions.checkState(
 379                    proposedMedia != null && proposedMedia.size() > 0,
 380                    "proposed media must be set when processing pre-approved session-initiate"
 381            );
 382            if (!this.proposedMedia.equals(contentMap.getMedia())) {
 383                sendSessionTerminate(Reason.SECURITY_ERROR, String.format(
 384                        "Your session proposal (Jingle Message Initiation) included media %s but your session-initiate was %s",
 385                        this.proposedMedia,
 386                        contentMap.getMedia()
 387                ));
 388                return;
 389            }
 390            target = State.SESSION_INITIALIZED_PRE_APPROVED;
 391        } else {
 392            target = State.SESSION_INITIALIZED;
 393        }
 394        if (transition(target, () -> this.initiatorRtpContentMap = contentMap)) {
 395            respondOk(jinglePacket);
 396
 397            final Set<Map.Entry<String, RtpContentMap.DescriptionTransport>> candidates = contentMap.contents.entrySet();
 398            if (candidates.size() > 0) {
 399                pendingIceCandidates.push(candidates);
 400            }
 401            if (target == State.SESSION_INITIALIZED_PRE_APPROVED) {
 402                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": automatically accepting session-initiate");
 403                sendSessionAccept();
 404            } else {
 405                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received not pre-approved session-initiate. start ringing");
 406                startRinging();
 407            }
 408        } else {
 409            Log.d(Config.LOGTAG, String.format("%s: received session-initiate while in state %s", id.account.getJid().asBareJid(), state));
 410            terminateWithOutOfOrder(jinglePacket);
 411        }
 412    }
 413
 414    private void receiveSessionAccept(final JinglePacket jinglePacket) {
 415        if (!isInitiator()) {
 416            Log.d(Config.LOGTAG, String.format("%s: received session-accept even though we were responding", id.account.getJid().asBareJid()));
 417            terminateWithOutOfOrder(jinglePacket);
 418            return;
 419        }
 420        final ListenableFuture<RtpContentMap> future = receiveRtpContentMap(jinglePacket, this.omemoVerification.hasFingerprint());
 421        Futures.addCallback(future, new FutureCallback<RtpContentMap>() {
 422            @Override
 423            public void onSuccess(@Nullable RtpContentMap rtpContentMap) {
 424                receiveSessionAccept(jinglePacket, rtpContentMap);
 425            }
 426
 427            @Override
 428            public void onFailure(@NonNull final Throwable throwable) {
 429                respondOk(jinglePacket);
 430                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": improperly formatted contents in session-accept", throwable);
 431                webRTCWrapper.close();
 432                sendSessionTerminate(Reason.ofThrowable(throwable), throwable.getMessage());
 433            }
 434        }, MoreExecutors.directExecutor());
 435    }
 436
 437    private void receiveSessionAccept(final JinglePacket jinglePacket, final RtpContentMap contentMap) {
 438        try {
 439            contentMap.requireContentDescriptions();
 440            contentMap.requireDTLSFingerprint();
 441        } catch (final RuntimeException e) {
 442            respondOk(jinglePacket);
 443            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": improperly formatted contents in session-accept", e);
 444            webRTCWrapper.close();
 445            sendSessionTerminate(Reason.of(e), e.getMessage());
 446            return;
 447        }
 448        final Set<Media> initiatorMedia = this.initiatorRtpContentMap.getMedia();
 449        if (!initiatorMedia.equals(contentMap.getMedia())) {
 450            sendSessionTerminate(Reason.SECURITY_ERROR, String.format(
 451                    "Your session-included included media %s but our session-initiate was %s",
 452                    this.proposedMedia,
 453                    contentMap.getMedia()
 454            ));
 455            return;
 456        }
 457        Log.d(Config.LOGTAG, "processing session-accept with " + contentMap.contents.size() + " contents");
 458        if (transition(State.SESSION_ACCEPTED)) {
 459            respondOk(jinglePacket);
 460            receiveSessionAccept(contentMap);
 461        } else {
 462            Log.d(Config.LOGTAG, String.format("%s: received session-accept while in state %s", id.account.getJid().asBareJid(), state));
 463            respondOk(jinglePacket);
 464        }
 465    }
 466
 467    private void receiveSessionAccept(final RtpContentMap contentMap) {
 468        this.responderRtpContentMap = contentMap;
 469        final SessionDescription sessionDescription;
 470        try {
 471            sessionDescription = SessionDescription.of(contentMap);
 472        } catch (final IllegalArgumentException | NullPointerException e) {
 473            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable convert offer from session-accept to SDP", e);
 474            webRTCWrapper.close();
 475            sendSessionTerminate(Reason.FAILED_APPLICATION, e.getMessage());
 476            return;
 477        }
 478        final org.webrtc.SessionDescription answer = new org.webrtc.SessionDescription(
 479                org.webrtc.SessionDescription.Type.ANSWER,
 480                sessionDescription.toString()
 481        );
 482        try {
 483            this.webRTCWrapper.setRemoteDescription(answer).get();
 484        } catch (final Exception e) {
 485            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable to set remote description after receiving session-accept", Throwables.getRootCause(e));
 486            webRTCWrapper.close();
 487            sendSessionTerminate(Reason.FAILED_APPLICATION);
 488            return;
 489        }
 490        final List<String> identificationTags = contentMap.group == null ? contentMap.getNames() : contentMap.group.getIdentificationTags();
 491        processCandidates(identificationTags, contentMap.contents.entrySet());
 492    }
 493
 494    private void sendSessionAccept() {
 495        final RtpContentMap rtpContentMap = this.initiatorRtpContentMap;
 496        if (rtpContentMap == null) {
 497            throw new IllegalStateException("initiator RTP Content Map has not been set");
 498        }
 499        final SessionDescription offer;
 500        try {
 501            offer = SessionDescription.of(rtpContentMap);
 502        } catch (final IllegalArgumentException | NullPointerException e) {
 503            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable convert offer from session-initiate to SDP", e);
 504            webRTCWrapper.close();
 505            sendSessionTerminate(Reason.FAILED_APPLICATION, e.getMessage());
 506            return;
 507        }
 508        sendSessionAccept(rtpContentMap.getMedia(), offer);
 509    }
 510
 511    private void sendSessionAccept(final Set<Media> media, final SessionDescription offer) {
 512        discoverIceServers(iceServers -> sendSessionAccept(media, offer, iceServers));
 513    }
 514
 515    private synchronized void sendSessionAccept(final Set<Media> media, final SessionDescription offer, final List<PeerConnection.IceServer> iceServers) {
 516        if (isTerminated()) {
 517            Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": ICE servers got discovered when session was already terminated. nothing to do.");
 518            return;
 519        }
 520        try {
 521            setupWebRTC(media, iceServers);
 522        } catch (final WebRTCWrapper.InitializationException e) {
 523            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable to initialize WebRTC");
 524            webRTCWrapper.close();
 525            sendSessionTerminate(Reason.FAILED_APPLICATION);
 526            return;
 527        }
 528        final org.webrtc.SessionDescription sdp = new org.webrtc.SessionDescription(
 529                org.webrtc.SessionDescription.Type.OFFER,
 530                offer.toString()
 531        );
 532        try {
 533            this.webRTCWrapper.setRemoteDescription(sdp).get();
 534            addIceCandidatesFromBlackLog();
 535            org.webrtc.SessionDescription webRTCSessionDescription = this.webRTCWrapper.createAnswer().get();
 536            prepareSessionAccept(webRTCSessionDescription);
 537        } catch (final Exception e) {
 538            failureToAcceptSession(e);
 539        }
 540    }
 541
 542    private void failureToAcceptSession(final Throwable throwable) {
 543        Log.d(Config.LOGTAG, "unable to send session accept", Throwables.getRootCause(throwable));
 544        webRTCWrapper.close();
 545        sendSessionTerminate(Reason.ofThrowable(throwable));
 546    }
 547
 548    private void addIceCandidatesFromBlackLog() {
 549        while (!this.pendingIceCandidates.isEmpty()) {
 550            processCandidates(this.pendingIceCandidates.poll());
 551            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": added candidates from back log");
 552        }
 553    }
 554
 555    private void prepareSessionAccept(final org.webrtc.SessionDescription webRTCSessionDescription) {
 556        final SessionDescription sessionDescription = SessionDescription.parse(webRTCSessionDescription.description);
 557        final RtpContentMap respondingRtpContentMap = RtpContentMap.of(sessionDescription);
 558        this.responderRtpContentMap = respondingRtpContentMap;
 559        final ListenableFuture<RtpContentMap> outgoingContentMapFuture = prepareOutgoingContentMap(respondingRtpContentMap);
 560        Futures.addCallback(outgoingContentMapFuture,
 561                new FutureCallback<RtpContentMap>() {
 562                    @Override
 563                    public void onSuccess(final RtpContentMap outgoingContentMap) {
 564                        sendSessionAccept(outgoingContentMap, webRTCSessionDescription);
 565                    }
 566
 567                    @Override
 568                    public void onFailure(@NonNull Throwable throwable) {
 569                        failureToAcceptSession(throwable);
 570                    }
 571                },
 572                MoreExecutors.directExecutor()
 573        );
 574    }
 575
 576    private void sendSessionAccept(final RtpContentMap rtpContentMap, final org.webrtc.SessionDescription webRTCSessionDescription) {
 577        transitionOrThrow(State.SESSION_ACCEPTED);
 578        final JinglePacket sessionAccept = rtpContentMap.toJinglePacket(JinglePacket.Action.SESSION_ACCEPT, id.sessionId);
 579        send(sessionAccept);
 580        try {
 581            webRTCWrapper.setLocalDescription(webRTCSessionDescription).get();
 582        } catch (Exception e) {
 583            failureToAcceptSession(e);
 584        }
 585    }
 586
 587    private ListenableFuture<RtpContentMap> prepareOutgoingContentMap(final RtpContentMap rtpContentMap) {
 588        if (this.omemoVerification.hasDeviceId()) {
 589            ListenableFuture<AxolotlService.OmemoVerifiedPayload<OmemoVerifiedRtpContentMap>> verifiedPayloadFuture = id.account.getAxolotlService()
 590                    .encrypt(rtpContentMap, id.with, omemoVerification.getDeviceId());
 591            return Futures.transform(verifiedPayloadFuture, verifiedPayload -> {
 592                omemoVerification.setOrEnsureEqual(verifiedPayload);
 593                return verifiedPayload.getPayload();
 594            }, MoreExecutors.directExecutor());
 595        } else {
 596            return Futures.immediateFuture(rtpContentMap);
 597        }
 598    }
 599
 600    synchronized void deliveryMessage(final Jid from, final Element message, final String serverMessageId, final long timestamp) {
 601        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": delivered message to JingleRtpConnection " + message);
 602        switch (message.getName()) {
 603            case "propose":
 604                receivePropose(from, Propose.upgrade(message), serverMessageId, timestamp);
 605                break;
 606            case "proceed":
 607                receiveProceed(from, Proceed.upgrade(message), serverMessageId, timestamp);
 608                break;
 609            case "retract":
 610                receiveRetract(from, serverMessageId, timestamp);
 611                break;
 612            case "reject":
 613                receiveReject(from, serverMessageId, timestamp);
 614                break;
 615            case "accept":
 616                receiveAccept(from, serverMessageId, timestamp);
 617                break;
 618            default:
 619                break;
 620        }
 621    }
 622
 623    void deliverFailedProceed() {
 624        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": receive message error for proceed message");
 625        if (transition(State.TERMINATED_CONNECTIVITY_ERROR)) {
 626            webRTCWrapper.close();
 627            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": transitioned into connectivity error");
 628            this.finish();
 629        }
 630    }
 631
 632    private void receiveAccept(final Jid from, final String serverMsgId, final long timestamp) {
 633        final boolean originatedFromMyself = from.asBareJid().equals(id.account.getJid().asBareJid());
 634        if (originatedFromMyself) {
 635            if (transition(State.ACCEPTED)) {
 636                if (serverMsgId != null) {
 637                    this.message.setServerMsgId(serverMsgId);
 638                }
 639                this.message.setTime(timestamp);
 640                this.message.setCarbon(true); //indicate that call was accepted on other device
 641                this.writeLogMessageSuccess(0);
 642                this.xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
 643                this.finish();
 644            } else {
 645                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable to transition to accept because already in state=" + this.state);
 646            }
 647        } else {
 648            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": ignoring 'accept' from " + from);
 649        }
 650    }
 651
 652    private void receiveReject(final Jid from, final String serverMsgId, final long timestamp) {
 653        final boolean originatedFromMyself = from.asBareJid().equals(id.account.getJid().asBareJid());
 654        //reject from another one of my clients
 655        if (originatedFromMyself) {
 656            receiveRejectFromMyself(serverMsgId, timestamp);
 657        } else if (isInitiator()) {
 658            if (from.equals(id.with)) {
 659                receiveRejectFromResponder();
 660            } else {
 661                Log.d(Config.LOGTAG, id.account.getJid() + ": ignoring reject from " + from + " for session with " + id.with);
 662            }
 663        } else {
 664            Log.d(Config.LOGTAG, id.account.getJid() + ": ignoring reject from " + from + " for session with " + id.with);
 665        }
 666    }
 667
 668    private void receiveRejectFromMyself(String serverMsgId, long timestamp) {
 669        if (transition(State.REJECTED)) {
 670            this.xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
 671            this.finish();
 672            if (serverMsgId != null) {
 673                this.message.setServerMsgId(serverMsgId);
 674            }
 675            this.message.setTime(timestamp);
 676            this.message.setCarbon(true); //indicate that call was rejected on other device
 677            writeLogMessageMissed();
 678        } else {
 679            Log.d(Config.LOGTAG, "not able to transition into REJECTED because already in " + this.state);
 680        }
 681    }
 682
 683    private void receiveRejectFromResponder() {
 684        if (isInState(State.PROCEED)) {
 685            Log.d(Config.LOGTAG, id.account.getJid() + ": received reject while still in proceed. callee reconsidered");
 686            closeTransitionLogFinish(State.REJECTED_RACED);
 687            return;
 688        }
 689        if (isInState(State.SESSION_INITIALIZED_PRE_APPROVED)) {
 690            Log.d(Config.LOGTAG, id.account.getJid() + ": received reject while in SESSION_INITIATED_PRE_APPROVED. callee reconsidered before receiving session-init");
 691            closeTransitionLogFinish(State.TERMINATED_DECLINED_OR_BUSY);
 692            return;
 693        }
 694        Log.d(Config.LOGTAG, id.account.getJid() + ": ignoring reject from responder because already in state " + this.state);
 695    }
 696
 697    private void receivePropose(final Jid from, final Propose propose, final String serverMsgId, final long timestamp) {
 698        final boolean originatedFromMyself = from.asBareJid().equals(id.account.getJid().asBareJid());
 699        if (originatedFromMyself) {
 700            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": saw proposal from myself. ignoring");
 701        } else if (transition(State.PROPOSED, () -> {
 702            final Collection<RtpDescription> descriptions = Collections2.transform(
 703                    Collections2.filter(propose.getDescriptions(), d -> d instanceof RtpDescription),
 704                    input -> (RtpDescription) input
 705            );
 706            final Collection<Media> media = Collections2.transform(descriptions, RtpDescription::getMedia);
 707            Preconditions.checkState(!media.contains(Media.UNKNOWN), "RTP descriptions contain unknown media");
 708            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received session proposal from " + from + " for " + media);
 709            this.proposedMedia = Sets.newHashSet(media);
 710        })) {
 711            if (serverMsgId != null) {
 712                this.message.setServerMsgId(serverMsgId);
 713            }
 714            this.message.setTime(timestamp);
 715            startRinging();
 716        } else {
 717            Log.d(Config.LOGTAG, id.account.getJid() + ": ignoring session proposal because already in " + state);
 718        }
 719    }
 720
 721    private void startRinging() {
 722        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received call from " + id.with + ". start ringing");
 723        ringingTimeoutFuture = jingleConnectionManager.schedule(this::ringingTimeout, BUSY_TIME_OUT, TimeUnit.SECONDS);
 724        xmppConnectionService.getNotificationService().startRinging(id, getMedia());
 725    }
 726
 727    private synchronized void ringingTimeout() {
 728        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": timeout reached for ringing");
 729        switch (this.state) {
 730            case PROPOSED:
 731                message.markUnread();
 732                rejectCallFromProposed();
 733                break;
 734            case SESSION_INITIALIZED:
 735                message.markUnread();
 736                rejectCallFromSessionInitiate();
 737                break;
 738        }
 739    }
 740
 741    private void cancelRingingTimeout() {
 742        final ScheduledFuture<?> future = this.ringingTimeoutFuture;
 743        if (future != null && !future.isCancelled()) {
 744            future.cancel(false);
 745        }
 746    }
 747
 748    private void receiveProceed(final Jid from, final Proceed proceed, final String serverMsgId, final long timestamp) {
 749        final Set<Media> media = Preconditions.checkNotNull(this.proposedMedia, "Proposed media has to be set before handling proceed");
 750        Preconditions.checkState(media.size() > 0, "Proposed media should not be empty");
 751        if (from.equals(id.with)) {
 752            if (isInitiator()) {
 753                if (transition(State.PROCEED)) {
 754                    if (serverMsgId != null) {
 755                        this.message.setServerMsgId(serverMsgId);
 756                    }
 757                    this.message.setTime(timestamp);
 758                    final Integer remoteDeviceId = proceed.getDeviceId();
 759                    if (isOmemoEnabled()) {
 760                        this.omemoVerification.setDeviceId(remoteDeviceId);
 761                    } else {
 762                        if (remoteDeviceId != null) {
 763                            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": remote party signaled support for OMEMO verification but we have OMEMO disabled");
 764                        }
 765                        this.omemoVerification.setDeviceId(null);
 766                    }
 767                    this.sendSessionInitiate(media, State.SESSION_INITIALIZED_PRE_APPROVED);
 768                } else {
 769                    Log.d(Config.LOGTAG, String.format("%s: ignoring proceed because already in %s", id.account.getJid().asBareJid(), this.state));
 770                }
 771            } else {
 772                Log.d(Config.LOGTAG, String.format("%s: ignoring proceed because we were not initializing", id.account.getJid().asBareJid()));
 773            }
 774        } else if (from.asBareJid().equals(id.account.getJid().asBareJid())) {
 775            if (transition(State.ACCEPTED)) {
 776                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": moved session with " + id.with + " into state accepted after received carbon copied procced");
 777                this.xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
 778                this.finish();
 779            }
 780        } else {
 781            Log.d(Config.LOGTAG, String.format("%s: ignoring proceed from %s. was expected from %s", id.account.getJid().asBareJid(), from, id.with));
 782        }
 783    }
 784
 785    private void receiveRetract(final Jid from, final String serverMsgId, final long timestamp) {
 786        if (from.equals(id.with)) {
 787            final State target = this.state == State.PROCEED ? State.RETRACTED_RACED : State.RETRACTED;
 788            if (transition(target)) {
 789                xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
 790                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": session with " + id.with + " has been retracted (serverMsgId=" + serverMsgId + ")");
 791                if (serverMsgId != null) {
 792                    this.message.setServerMsgId(serverMsgId);
 793                }
 794                this.message.setTime(timestamp);
 795                if (target == State.RETRACTED) {
 796                    this.message.markUnread();
 797                }
 798                writeLogMessageMissed();
 799                finish();
 800            } else {
 801                Log.d(Config.LOGTAG, "ignoring retract because already in " + this.state);
 802            }
 803        } else {
 804            //TODO parse retract from self
 805            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received retract from " + from + ". expected retract from" + id.with + ". ignoring");
 806        }
 807    }
 808
 809    public void sendSessionInitiate() {
 810        sendSessionInitiate(this.proposedMedia, State.SESSION_INITIALIZED);
 811    }
 812
 813    private void sendSessionInitiate(final Set<Media> media, final State targetState) {
 814        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": prepare session-initiate");
 815        discoverIceServers(iceServers -> sendSessionInitiate(media, targetState, iceServers));
 816    }
 817
 818    private synchronized void sendSessionInitiate(final Set<Media> media, final State targetState, final List<PeerConnection.IceServer> iceServers) {
 819        if (isTerminated()) {
 820            Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": ICE servers got discovered when session was already terminated. nothing to do.");
 821            return;
 822        }
 823        try {
 824            setupWebRTC(media, iceServers);
 825        } catch (final WebRTCWrapper.InitializationException e) {
 826            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable to initialize WebRTC");
 827            webRTCWrapper.close();
 828            sendRetract(Reason.ofThrowable(e));
 829            return;
 830        }
 831        try {
 832            org.webrtc.SessionDescription webRTCSessionDescription = this.webRTCWrapper.createOffer().get();
 833            prepareSessionInitiate(webRTCSessionDescription, targetState);
 834        } catch (final Exception e) {
 835            failureToInitiateSession(e, targetState);
 836        }
 837    }
 838
 839    private void failureToInitiateSession(final Throwable throwable, final State targetState) {
 840        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable to sendSessionInitiate", Throwables.getRootCause(throwable));
 841        webRTCWrapper.close();
 842        final Reason reason = Reason.ofThrowable(throwable);
 843        if (isInState(targetState)) {
 844            sendSessionTerminate(reason);
 845        } else {
 846            sendRetract(reason);
 847        }
 848    }
 849
 850    private void sendRetract(final Reason reason) {
 851        //TODO embed reason into retract
 852        sendJingleMessage("retract", id.with.asBareJid());
 853        transitionOrThrow(reasonToState(reason));
 854        this.finish();
 855    }
 856
 857    private void prepareSessionInitiate(final org.webrtc.SessionDescription webRTCSessionDescription, final State targetState) {
 858        final SessionDescription sessionDescription = SessionDescription.parse(webRTCSessionDescription.description);
 859        final RtpContentMap rtpContentMap = RtpContentMap.of(sessionDescription);
 860        this.initiatorRtpContentMap = rtpContentMap;
 861        final ListenableFuture<RtpContentMap> outgoingContentMapFuture = encryptSessionInitiate(rtpContentMap);
 862        Futures.addCallback(outgoingContentMapFuture, new FutureCallback<RtpContentMap>() {
 863            @Override
 864            public void onSuccess(final RtpContentMap outgoingContentMap) {
 865                sendSessionInitiate(outgoingContentMap, webRTCSessionDescription, targetState);
 866            }
 867
 868            @Override
 869            public void onFailure(@NonNull final Throwable throwable) {
 870                failureToInitiateSession(throwable, targetState);
 871            }
 872        }, MoreExecutors.directExecutor());
 873    }
 874
 875    private void sendSessionInitiate(final RtpContentMap rtpContentMap, final org.webrtc.SessionDescription webRTCSessionDescription, final State targetState) {
 876        this.transitionOrThrow(targetState);
 877        final JinglePacket sessionInitiate = rtpContentMap.toJinglePacket(JinglePacket.Action.SESSION_INITIATE, id.sessionId);
 878        send(sessionInitiate);
 879        try {
 880            this.webRTCWrapper.setLocalDescription(webRTCSessionDescription).get();
 881        } catch (Exception e) {
 882            failureToInitiateSession(e, targetState);
 883        }
 884    }
 885
 886    private ListenableFuture<RtpContentMap> encryptSessionInitiate(final RtpContentMap rtpContentMap) {
 887        if (this.omemoVerification.hasDeviceId()) {
 888            final ListenableFuture<AxolotlService.OmemoVerifiedPayload<OmemoVerifiedRtpContentMap>> verifiedPayloadFuture = id.account.getAxolotlService()
 889                    .encrypt(rtpContentMap, id.with, omemoVerification.getDeviceId());
 890            final ListenableFuture<RtpContentMap> future = Futures.transform(verifiedPayloadFuture, verifiedPayload -> {
 891                omemoVerification.setSessionFingerprint(verifiedPayload.getFingerprint());
 892                return verifiedPayload.getPayload();
 893            }, MoreExecutors.directExecutor());
 894            if (Config.REQUIRE_RTP_VERIFICATION) {
 895                return future;
 896            }
 897            return Futures.catching(
 898                    future,
 899                    CryptoFailedException.class,
 900                    e -> {
 901                        Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable to use OMEMO DTLS verification on outgoing session initiate. falling back", e);
 902                        return rtpContentMap;
 903                    },
 904                    MoreExecutors.directExecutor()
 905            );
 906        } else {
 907            return Futures.immediateFuture(rtpContentMap);
 908        }
 909    }
 910
 911    private void sendSessionTerminate(final Reason reason) {
 912        sendSessionTerminate(reason, null);
 913    }
 914
 915    private void sendSessionTerminate(final Reason reason, final String text) {
 916        final State previous = this.state;
 917        final State target = reasonToState(reason);
 918        transitionOrThrow(target);
 919        if (previous != State.NULL) {
 920            writeLogMessage(target);
 921        }
 922        final JinglePacket jinglePacket = new JinglePacket(JinglePacket.Action.SESSION_TERMINATE, id.sessionId);
 923        jinglePacket.setReason(reason, text);
 924        Log.d(Config.LOGTAG, jinglePacket.toString());
 925        send(jinglePacket);
 926        finish();
 927    }
 928
 929    private void sendTransportInfo(final String contentName, IceUdpTransportInfo.Candidate candidate) {
 930        final RtpContentMap transportInfo;
 931        try {
 932            final RtpContentMap rtpContentMap = isInitiator() ? this.initiatorRtpContentMap : this.responderRtpContentMap;
 933            transportInfo = rtpContentMap.transportInfo(contentName, candidate);
 934        } catch (final Exception e) {
 935            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": unable to prepare transport-info from candidate for content=" + contentName);
 936            return;
 937        }
 938        final JinglePacket jinglePacket = transportInfo.toJinglePacket(JinglePacket.Action.TRANSPORT_INFO, id.sessionId);
 939        send(jinglePacket);
 940    }
 941
 942    private void send(final JinglePacket jinglePacket) {
 943        jinglePacket.setTo(id.with);
 944        xmppConnectionService.sendIqPacket(id.account, jinglePacket, this::handleIqResponse);
 945    }
 946
 947    private synchronized void handleIqResponse(final Account account, final IqPacket response) {
 948        if (response.getType() == IqPacket.TYPE.ERROR) {
 949            final String errorCondition = response.getErrorCondition();
 950            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received IQ-error from " + response.getFrom() + " in RTP session. " + errorCondition);
 951            if (isTerminated()) {
 952                Log.i(Config.LOGTAG, id.account.getJid().asBareJid() + ": ignoring error because session was already terminated");
 953                return;
 954            }
 955            this.webRTCWrapper.close();
 956            final State target;
 957            if (Arrays.asList(
 958                    "service-unavailable",
 959                    "recipient-unavailable",
 960                    "remote-server-not-found",
 961                    "remote-server-timeout"
 962            ).contains(errorCondition)) {
 963                target = State.TERMINATED_CONNECTIVITY_ERROR;
 964            } else {
 965                target = State.TERMINATED_APPLICATION_FAILURE;
 966            }
 967            transitionOrThrow(target);
 968            this.finish();
 969        } else if (response.getType() == IqPacket.TYPE.TIMEOUT) {
 970            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": received IQ timeout in RTP session with " + id.with + ". terminating with connectivity error");
 971            if (isTerminated()) {
 972                Log.i(Config.LOGTAG, id.account.getJid().asBareJid() + ": ignoring error because session was already terminated");
 973                return;
 974            }
 975            this.webRTCWrapper.close();
 976            transitionOrThrow(State.TERMINATED_CONNECTIVITY_ERROR);
 977            this.finish();
 978        }
 979    }
 980
 981    private void terminateWithOutOfOrder(final JinglePacket jinglePacket) {
 982        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": terminating session with out-of-order");
 983        this.webRTCWrapper.close();
 984        transitionOrThrow(State.TERMINATED_APPLICATION_FAILURE);
 985        respondWithOutOfOrder(jinglePacket);
 986        this.finish();
 987    }
 988
 989    private void respondWithOutOfOrder(final JinglePacket jinglePacket) {
 990        jingleConnectionManager.respondWithJingleError(id.account, jinglePacket, "out-of-order", "unexpected-request", "wait");
 991    }
 992
 993    private void respondOk(final JinglePacket jinglePacket) {
 994        xmppConnectionService.sendIqPacket(id.account, jinglePacket.generateResponse(IqPacket.TYPE.RESULT), null);
 995    }
 996
 997    public void throwStateTransitionException() {
 998        final StateTransitionException exception = this.stateTransitionException;
 999        if (exception != null) {
1000            throw new IllegalStateException(String.format("Transition to %s did not call finish", exception.state), exception);
1001        }
1002    }
1003
1004    public RtpEndUserState getEndUserState() {
1005        switch (this.state) {
1006            case NULL:
1007            case PROPOSED:
1008            case SESSION_INITIALIZED:
1009                if (isInitiator()) {
1010                    return RtpEndUserState.RINGING;
1011                } else {
1012                    return RtpEndUserState.INCOMING_CALL;
1013                }
1014            case PROCEED:
1015                if (isInitiator()) {
1016                    return RtpEndUserState.RINGING;
1017                } else {
1018                    return RtpEndUserState.ACCEPTING_CALL;
1019                }
1020            case SESSION_INITIALIZED_PRE_APPROVED:
1021                if (isInitiator()) {
1022                    return RtpEndUserState.RINGING;
1023                } else {
1024                    return RtpEndUserState.CONNECTING;
1025                }
1026            case SESSION_ACCEPTED:
1027                final PeerConnection.PeerConnectionState state;
1028                try {
1029                    state = webRTCWrapper.getState();
1030                } catch (final WebRTCWrapper.PeerConnectionNotInitialized e) {
1031                    //We usually close the WebRTCWrapper *before* transitioning so we might still
1032                    //be in SESSION_ACCEPTED even though the peerConnection has been torn down
1033                    return RtpEndUserState.ENDING_CALL;
1034                }
1035                if (state == PeerConnection.PeerConnectionState.CONNECTED) {
1036                    return RtpEndUserState.CONNECTED;
1037                } else if (state == PeerConnection.PeerConnectionState.NEW || state == PeerConnection.PeerConnectionState.CONNECTING) {
1038                    return RtpEndUserState.CONNECTING;
1039                } else if (state == PeerConnection.PeerConnectionState.CLOSED) {
1040                    return RtpEndUserState.ENDING_CALL;
1041                } else {
1042                    return rtpConnectionStarted == 0 ? RtpEndUserState.CONNECTIVITY_ERROR : RtpEndUserState.CONNECTIVITY_LOST_ERROR;
1043                }
1044            case REJECTED:
1045            case REJECTED_RACED:
1046            case TERMINATED_DECLINED_OR_BUSY:
1047                if (isInitiator()) {
1048                    return RtpEndUserState.DECLINED_OR_BUSY;
1049                } else {
1050                    return RtpEndUserState.ENDED;
1051                }
1052            case TERMINATED_SUCCESS:
1053            case ACCEPTED:
1054            case RETRACTED:
1055            case TERMINATED_CANCEL_OR_TIMEOUT:
1056                return RtpEndUserState.ENDED;
1057            case RETRACTED_RACED:
1058                if (isInitiator()) {
1059                    return RtpEndUserState.ENDED;
1060                } else {
1061                    return RtpEndUserState.RETRACTED;
1062                }
1063            case TERMINATED_CONNECTIVITY_ERROR:
1064                return rtpConnectionStarted == 0 ? RtpEndUserState.CONNECTIVITY_ERROR : RtpEndUserState.CONNECTIVITY_LOST_ERROR;
1065            case TERMINATED_APPLICATION_FAILURE:
1066                return RtpEndUserState.APPLICATION_ERROR;
1067            case TERMINATED_SECURITY_ERROR:
1068                return RtpEndUserState.SECURITY_ERROR;
1069        }
1070        throw new IllegalStateException(String.format("%s has no equivalent EndUserState", this.state));
1071    }
1072
1073    public Set<Media> getMedia() {
1074        final State current = getState();
1075        if (current == State.NULL) {
1076            if (isInitiator()) {
1077                return Preconditions.checkNotNull(
1078                        this.proposedMedia,
1079                        "RTP connection has not been initialized properly"
1080                );
1081            }
1082            throw new IllegalStateException("RTP connection has not been initialized yet");
1083        }
1084        if (Arrays.asList(State.PROPOSED, State.PROCEED).contains(current)) {
1085            return Preconditions.checkNotNull(
1086                    this.proposedMedia,
1087                    "RTP connection has not been initialized properly"
1088            );
1089        }
1090        final RtpContentMap initiatorContentMap = initiatorRtpContentMap;
1091        if (initiatorContentMap != null) {
1092            return initiatorContentMap.getMedia();
1093        } else if (isTerminated()) {
1094            return Collections.emptySet(); //we might fail before we ever got a chance to set media
1095        } else {
1096            return Preconditions.checkNotNull(this.proposedMedia, "RTP connection has not been initialized properly");
1097        }
1098    }
1099
1100
1101    public boolean isVerified() {
1102        final String fingerprint = this.omemoVerification.getFingerprint();
1103        if (fingerprint == null) {
1104            return false;
1105        }
1106        final FingerprintStatus status = id.account.getAxolotlService().getFingerprintTrust(fingerprint);
1107        return status != null && status.isVerified();
1108    }
1109
1110    public synchronized void acceptCall() {
1111        switch (this.state) {
1112            case PROPOSED:
1113                cancelRingingTimeout();
1114                acceptCallFromProposed();
1115                break;
1116            case SESSION_INITIALIZED:
1117                cancelRingingTimeout();
1118                acceptCallFromSessionInitialized();
1119                break;
1120            case ACCEPTED:
1121                Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": the call has already been accepted  with another client. UI was just lagging behind");
1122                break;
1123            case PROCEED:
1124            case SESSION_ACCEPTED:
1125                Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": the call has already been accepted. user probably double tapped the UI");
1126                break;
1127            default:
1128                throw new IllegalStateException("Can not accept call from " + this.state);
1129        }
1130    }
1131
1132
1133    public void notifyPhoneCall() {
1134        Log.d(Config.LOGTAG, "a phone call has just been started. killing jingle rtp connections");
1135        if (Arrays.asList(State.PROPOSED, State.SESSION_INITIALIZED).contains(this.state)) {
1136            rejectCall();
1137        } else {
1138            endCall();
1139        }
1140    }
1141
1142    public synchronized void rejectCall() {
1143        if (isTerminated()) {
1144            Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": received rejectCall() when session has already been terminated. nothing to do");
1145            return;
1146        }
1147        switch (this.state) {
1148            case PROPOSED:
1149                rejectCallFromProposed();
1150                break;
1151            case SESSION_INITIALIZED:
1152                rejectCallFromSessionInitiate();
1153                break;
1154            default:
1155                throw new IllegalStateException("Can not reject call from " + this.state);
1156        }
1157    }
1158
1159    public synchronized void endCall() {
1160        if (isTerminated()) {
1161            Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": received endCall() when session has already been terminated. nothing to do");
1162            return;
1163        }
1164        if (isInState(State.PROPOSED) && !isInitiator()) {
1165            rejectCallFromProposed();
1166            return;
1167        }
1168        if (isInState(State.PROCEED)) {
1169            if (isInitiator()) {
1170                retractFromProceed();
1171            } else {
1172                rejectCallFromProceed();
1173            }
1174            return;
1175        }
1176        if (isInitiator() && isInState(State.SESSION_INITIALIZED, State.SESSION_INITIALIZED_PRE_APPROVED)) {
1177            this.webRTCWrapper.close();
1178            sendSessionTerminate(Reason.CANCEL);
1179            return;
1180        }
1181        if (isInState(State.SESSION_INITIALIZED)) {
1182            rejectCallFromSessionInitiate();
1183            return;
1184        }
1185        if (isInState(State.SESSION_INITIALIZED_PRE_APPROVED, State.SESSION_ACCEPTED)) {
1186            this.webRTCWrapper.close();
1187            sendSessionTerminate(Reason.SUCCESS);
1188            return;
1189        }
1190        if (isInState(State.TERMINATED_APPLICATION_FAILURE, State.TERMINATED_CONNECTIVITY_ERROR, State.TERMINATED_DECLINED_OR_BUSY)) {
1191            Log.d(Config.LOGTAG, "ignoring request to end call because already in state " + this.state);
1192            return;
1193        }
1194        throw new IllegalStateException("called 'endCall' while in state " + this.state + ". isInitiator=" + isInitiator());
1195    }
1196
1197    private void retractFromProceed() {
1198        Log.d(Config.LOGTAG, "retract from proceed");
1199        this.sendJingleMessage("retract");
1200        closeTransitionLogFinish(State.RETRACTED_RACED);
1201    }
1202
1203    private void closeTransitionLogFinish(final State state) {
1204        this.webRTCWrapper.close();
1205        transitionOrThrow(state);
1206        writeLogMessage(state);
1207        finish();
1208    }
1209
1210    private void setupWebRTC(final Set<Media> media, final List<PeerConnection.IceServer> iceServers) throws WebRTCWrapper.InitializationException {
1211        this.jingleConnectionManager.ensureConnectionIsRegistered(this);
1212        final AppRTCAudioManager.SpeakerPhonePreference speakerPhonePreference;
1213        if (media.contains(Media.VIDEO)) {
1214            speakerPhonePreference = AppRTCAudioManager.SpeakerPhonePreference.SPEAKER;
1215        } else {
1216            speakerPhonePreference = AppRTCAudioManager.SpeakerPhonePreference.EARPIECE;
1217        }
1218        this.webRTCWrapper.setup(this.xmppConnectionService, speakerPhonePreference);
1219        this.webRTCWrapper.initializePeerConnection(media, iceServers);
1220    }
1221
1222    private void acceptCallFromProposed() {
1223        transitionOrThrow(State.PROCEED);
1224        xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
1225        this.sendJingleMessage("accept", id.account.getJid().asBareJid());
1226        this.sendJingleMessage("proceed");
1227    }
1228
1229    private void rejectCallFromProposed() {
1230        transitionOrThrow(State.REJECTED);
1231        writeLogMessageMissed();
1232        xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
1233        this.sendJingleMessage("reject");
1234        finish();
1235    }
1236
1237    private void rejectCallFromProceed() {
1238        this.sendJingleMessage("reject");
1239        closeTransitionLogFinish(State.REJECTED_RACED);
1240    }
1241
1242    private void rejectCallFromSessionInitiate() {
1243        webRTCWrapper.close();
1244        sendSessionTerminate(Reason.DECLINE);
1245        xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
1246    }
1247
1248    private void sendJingleMessage(final String action) {
1249        sendJingleMessage(action, id.with);
1250    }
1251
1252    private void sendJingleMessage(final String action, final Jid to) {
1253        final MessagePacket messagePacket = new MessagePacket();
1254        messagePacket.setType(MessagePacket.TYPE_CHAT); //we want to carbon copy those
1255        messagePacket.setTo(to);
1256        final Element intent = messagePacket.addChild(action, Namespace.JINGLE_MESSAGE).setAttribute("id", id.sessionId);
1257        if ("proceed".equals(action)) {
1258            messagePacket.setId(JINGLE_MESSAGE_PROCEED_ID_PREFIX + id.sessionId);
1259            if (isOmemoEnabled()) {
1260                final int deviceId = id.account.getAxolotlService().getOwnDeviceId();
1261                final Element device = intent.addChild("device", Namespace.OMEMO_DTLS_SRTP_VERIFICATION);
1262                device.setAttribute("id", deviceId);
1263            }
1264        }
1265        messagePacket.addChild("store", "urn:xmpp:hints");
1266        xmppConnectionService.sendMessagePacket(id.account, messagePacket);
1267    }
1268
1269    private boolean isOmemoEnabled() {
1270        final Conversational conversational = message.getConversation();
1271        if (conversational instanceof Conversation) {
1272            return ((Conversation) conversational).getNextEncryption() == Message.ENCRYPTION_AXOLOTL;
1273        }
1274        return false;
1275    }
1276
1277    private void acceptCallFromSessionInitialized() {
1278        xmppConnectionService.getNotificationService().cancelIncomingCallNotification();
1279        sendSessionAccept();
1280    }
1281
1282    private synchronized boolean isInState(State... state) {
1283        return Arrays.asList(state).contains(this.state);
1284    }
1285
1286    private boolean transition(final State target) {
1287        return transition(target, null);
1288    }
1289
1290    private synchronized boolean transition(final State target, final Runnable runnable) {
1291        final Collection<State> validTransitions = VALID_TRANSITIONS.get(this.state);
1292        if (validTransitions != null && validTransitions.contains(target)) {
1293            this.state = target;
1294            this.stateTransitionException = new StateTransitionException(target);
1295            if (runnable != null) {
1296                runnable.run();
1297            }
1298            Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": transitioned into " + target);
1299            updateEndUserState();
1300            updateOngoingCallNotification();
1301            return true;
1302        } else {
1303            return false;
1304        }
1305    }
1306
1307    void transitionOrThrow(final State target) {
1308        if (!transition(target)) {
1309            throw new IllegalStateException(String.format("Unable to transition from %s to %s", this.state, target));
1310        }
1311    }
1312
1313    @Override
1314    public void onIceCandidate(final IceCandidate iceCandidate) {
1315        final IceUdpTransportInfo.Candidate candidate = IceUdpTransportInfo.Candidate.fromSdpAttribute(iceCandidate.sdp);
1316        Log.d(Config.LOGTAG, "sending candidate: " + iceCandidate.toString());
1317        sendTransportInfo(iceCandidate.sdpMid, candidate);
1318    }
1319
1320    @Override
1321    public void onConnectionChange(final PeerConnection.PeerConnectionState newState) {
1322        Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": PeerConnectionState changed to " + newState);
1323        if (newState == PeerConnection.PeerConnectionState.CONNECTED && this.rtpConnectionStarted == 0) {
1324            this.rtpConnectionStarted = SystemClock.elapsedRealtime();
1325        }
1326        if (newState == PeerConnection.PeerConnectionState.CLOSED && this.rtpConnectionEnded == 0) {
1327            this.rtpConnectionEnded = SystemClock.elapsedRealtime();
1328        }
1329        //TODO 'DISCONNECTED' might be an opportunity to renew the offer and send a transport-replace
1330        //TODO exact syntax is yet to be determined but transport-replace sounds like the most reasonable
1331        //as there is no content-replace
1332        if (Arrays.asList(PeerConnection.PeerConnectionState.FAILED, PeerConnection.PeerConnectionState.DISCONNECTED).contains(newState)) {
1333            if (isTerminated()) {
1334                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": not sending session-terminate after connectivity error because session is already in state " + this.state);
1335                return;
1336            }
1337            new Thread(this::closeWebRTCSessionAfterFailedConnection).start();
1338        } else {
1339            updateEndUserState();
1340        }
1341    }
1342
1343    private void closeWebRTCSessionAfterFailedConnection() {
1344        this.webRTCWrapper.close();
1345        synchronized (this) {
1346            if (isTerminated()) {
1347                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": no need to send session-terminate after failed connection. Other party already did");
1348                return;
1349            }
1350            sendSessionTerminate(Reason.CONNECTIVITY_ERROR);
1351        }
1352    }
1353
1354    public long getRtpConnectionStarted() {
1355        return this.rtpConnectionStarted;
1356    }
1357
1358    public long getRtpConnectionEnded() {
1359        return this.rtpConnectionEnded;
1360    }
1361
1362    public AppRTCAudioManager getAudioManager() {
1363        return webRTCWrapper.getAudioManager();
1364    }
1365
1366    public boolean isMicrophoneEnabled() {
1367        return webRTCWrapper.isMicrophoneEnabled();
1368    }
1369
1370    public boolean setMicrophoneEnabled(final boolean enabled) {
1371        return webRTCWrapper.setMicrophoneEnabled(enabled);
1372    }
1373
1374    public boolean isVideoEnabled() {
1375        return webRTCWrapper.isVideoEnabled();
1376    }
1377
1378    public void setVideoEnabled(final boolean enabled) {
1379        webRTCWrapper.setVideoEnabled(enabled);
1380    }
1381
1382    public boolean isCameraSwitchable() {
1383        return webRTCWrapper.isCameraSwitchable();
1384    }
1385
1386    public boolean isFrontCamera() {
1387        return webRTCWrapper.isFrontCamera();
1388    }
1389
1390    public ListenableFuture<Boolean> switchCamera() {
1391        return webRTCWrapper.switchCamera();
1392    }
1393
1394    @Override
1395    public void onAudioDeviceChanged(AppRTCAudioManager.AudioDevice selectedAudioDevice, Set<AppRTCAudioManager.AudioDevice> availableAudioDevices) {
1396        xmppConnectionService.notifyJingleRtpConnectionUpdate(selectedAudioDevice, availableAudioDevices);
1397    }
1398
1399    private void updateEndUserState() {
1400        final RtpEndUserState endUserState = getEndUserState();
1401        jingleConnectionManager.toneManager.transition(isInitiator(), endUserState, getMedia());
1402        xmppConnectionService.notifyJingleRtpConnectionUpdate(id.account, id.with, id.sessionId, endUserState);
1403    }
1404
1405    private void updateOngoingCallNotification() {
1406        if (STATES_SHOWING_ONGOING_CALL.contains(this.state)) {
1407            xmppConnectionService.setOngoingCall(id, getMedia());
1408        } else {
1409            xmppConnectionService.removeOngoingCall();
1410        }
1411    }
1412
1413    private void discoverIceServers(final OnIceServersDiscovered onIceServersDiscovered) {
1414        if (id.account.getXmppConnection().getFeatures().externalServiceDiscovery()) {
1415            final IqPacket request = new IqPacket(IqPacket.TYPE.GET);
1416            request.setTo(id.account.getDomain());
1417            request.addChild("services", Namespace.EXTERNAL_SERVICE_DISCOVERY);
1418            xmppConnectionService.sendIqPacket(id.account, request, (account, response) -> {
1419                ImmutableList.Builder<PeerConnection.IceServer> listBuilder = new ImmutableList.Builder<>();
1420                if (response.getType() == IqPacket.TYPE.RESULT) {
1421                    final Element services = response.findChild("services", Namespace.EXTERNAL_SERVICE_DISCOVERY);
1422                    final List<Element> children = services == null ? Collections.emptyList() : services.getChildren();
1423                    for (final Element child : children) {
1424                        if ("service".equals(child.getName())) {
1425                            final String type = child.getAttribute("type");
1426                            final String host = child.getAttribute("host");
1427                            final String sport = child.getAttribute("port");
1428                            final Integer port = sport == null ? null : Ints.tryParse(sport);
1429                            final String transport = child.getAttribute("transport");
1430                            final String username = child.getAttribute("username");
1431                            final String password = child.getAttribute("password");
1432                            if (Strings.isNullOrEmpty(host) || port == null) {
1433                                continue;
1434                            }
1435                            if (port < 0 || port > 65535) {
1436                                continue;
1437                            }
1438                            if (Arrays.asList("stun", "stuns", "turn", "turns").contains(type) && Arrays.asList("udp", "tcp").contains(transport)) {
1439                                if (Arrays.asList("stuns", "turns").contains(type) && "udp".equals(transport)) {
1440                                    Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": skipping invalid combination of udp/tls in external services");
1441                                    continue;
1442                                }
1443                                final PeerConnection.IceServer.Builder iceServerBuilder = PeerConnection.IceServer
1444                                        .builder(String.format("%s:%s:%s?transport=%s", type, IP.wrapIPv6(host), port, transport));
1445                                iceServerBuilder.setTlsCertPolicy(PeerConnection.TlsCertPolicy.TLS_CERT_POLICY_INSECURE_NO_CHECK);
1446                                if (username != null && password != null) {
1447                                    iceServerBuilder.setUsername(username);
1448                                    iceServerBuilder.setPassword(password);
1449                                } else if (Arrays.asList("turn", "turns").contains(type)) {
1450                                    //The WebRTC spec requires throwing an InvalidAccessError when username (from libwebrtc source coder)
1451                                    //https://chromium.googlesource.com/external/webrtc/+/master/pc/ice_server_parsing.cc
1452                                    Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": skipping " + type + "/" + transport + " without username and password");
1453                                    continue;
1454                                }
1455                                final PeerConnection.IceServer iceServer = iceServerBuilder.createIceServer();
1456                                Log.d(Config.LOGTAG, id.account.getJid().asBareJid() + ": discovered ICE Server: " + iceServer);
1457                                listBuilder.add(iceServer);
1458                            }
1459                        }
1460                    }
1461                }
1462                final List<PeerConnection.IceServer> iceServers = listBuilder.build();
1463                if (iceServers.size() == 0) {
1464                    Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": no ICE server found " + response);
1465                }
1466                onIceServersDiscovered.onIceServersDiscovered(iceServers);
1467            });
1468        } else {
1469            Log.w(Config.LOGTAG, id.account.getJid().asBareJid() + ": has no external service discovery");
1470            onIceServersDiscovered.onIceServersDiscovered(Collections.emptyList());
1471        }
1472    }
1473
1474    private void finish() {
1475        if (isTerminated()) {
1476            this.cancelRingingTimeout();
1477            this.webRTCWrapper.verifyClosed();
1478            this.jingleConnectionManager.setTerminalSessionState(id, getEndUserState(), getMedia());
1479            this.jingleConnectionManager.finishConnectionOrThrow(this);
1480        } else {
1481            throw new IllegalStateException(String.format("Unable to call finish from %s", this.state));
1482        }
1483    }
1484
1485    private void writeLogMessage(final State state) {
1486        final long started = this.rtpConnectionStarted;
1487        long duration = started <= 0 ? 0 : SystemClock.elapsedRealtime() - started;
1488        if (state == State.TERMINATED_SUCCESS || (state == State.TERMINATED_CONNECTIVITY_ERROR && duration > 0)) {
1489            writeLogMessageSuccess(duration);
1490        } else {
1491            writeLogMessageMissed();
1492        }
1493    }
1494
1495    private void writeLogMessageSuccess(final long duration) {
1496        this.message.setBody(new RtpSessionStatus(true, duration).toString());
1497        this.writeMessage();
1498    }
1499
1500    private void writeLogMessageMissed() {
1501        this.message.setBody(new RtpSessionStatus(false, 0).toString());
1502        this.writeMessage();
1503    }
1504
1505    private void writeMessage() {
1506        final Conversational conversational = message.getConversation();
1507        if (conversational instanceof Conversation) {
1508            ((Conversation) conversational).add(this.message);
1509            xmppConnectionService.createMessageAsync(message);
1510            xmppConnectionService.updateConversationUi();
1511        } else {
1512            throw new IllegalStateException("Somehow the conversation in a message was a stub");
1513        }
1514    }
1515
1516    public State getState() {
1517        return this.state;
1518    }
1519
1520    boolean isTerminated() {
1521        return TERMINATED.contains(this.state);
1522    }
1523
1524    public Optional<VideoTrack> getLocalVideoTrack() {
1525        return webRTCWrapper.getLocalVideoTrack();
1526    }
1527
1528    public Optional<VideoTrack> getRemoteVideoTrack() {
1529        return webRTCWrapper.getRemoteVideoTrack();
1530    }
1531
1532
1533    public EglBase.Context getEglBaseContext() {
1534        return webRTCWrapper.getEglBaseContext();
1535    }
1536
1537    void setProposedMedia(final Set<Media> media) {
1538        this.proposedMedia = media;
1539    }
1540
1541    public void fireStateUpdate() {
1542        final RtpEndUserState endUserState = getEndUserState();
1543        xmppConnectionService.notifyJingleRtpConnectionUpdate(id.account, id.with, id.sessionId, endUserState);
1544    }
1545
1546    private interface OnIceServersDiscovered {
1547        void onIceServersDiscovered(List<PeerConnection.IceServer> iceServers);
1548    }
1549
1550    private static class StateTransitionException extends Exception {
1551        private final State state;
1552
1553        private StateTransitionException(final State state) {
1554            this.state = state;
1555        }
1556    }
1557}