private void initWallet() {
new LinuxSecureRandom(); // init proper random number generator
initLogging();
Threading.throwOnLockCycles();
log.info(
"=== starting app using configuration: {}, {}",
Constants.TEST ? "test" : "prod",
Constants.NETWORK_PARAMETERS.getId());
super.onCreate();
CrashReporter.init(getCacheDir());
Threading.uncaughtExceptionHandler =
new Thread.UncaughtExceptionHandler() {
@Override
public void uncaughtException(final Thread thread, final Throwable throwable) {
log.info("peercoinj uncaught exception", throwable);
CrashReporter.saveBackgroundTrace(throwable, packageInfo);
}
};
initMnemonicCode();
config = new Configuration(PreferenceManager.getDefaultSharedPreferences(this));
walletFile = getFileStreamPath(Constants.Files.WALLET_FILENAME_PROTOBUF);
// Rename old wallets
final File oldWalletFile = getFileStreamPath(Constants.Files.WALLET_FILENAME_PROTOBUF_OLD);
if (oldWalletFile.exists()) oldWalletFile.renameTo(walletFile);
loadWalletFromProtobuf();
config.updateLastVersionCode(packageInfo.versionCode);
afterLoadWallet();
cleanupFiles();
synchronized (this) {
isLoaded = true;
for (Runnable callback : loadedCallbacks) callback.run();
}
}
/**
* A handler class which handles most of the complexity of creating a payment channel connection by
* providing a simple in/out interface which is provided with protobufs from the client and which
* generates protobufs which should be sent to the client.
*
* <p>Does all required verification of messages and properly stores state objects in the
* wallet-attached {@link StoredPaymentChannelServerStates} so that they are automatically closed
* when necessary and payment transactions are not lost if the application crashes before it
* unlocks.
*/
public class PaymentChannelServer {
// TODO: Update JavaDocs with notes for communication over stateless protocols
private static final org.slf4j.Logger log = LoggerFactory.getLogger(PaymentChannelServer.class);
protected final ReentrantLock lock = Threading.lock("channelserver");
public final int SERVER_MAJOR_VERSION = 1;
public final int SERVER_MINOR_VERSION = 0;
// The step in the initialization process we are in, some of this is duplicated in the
// PaymentChannelServerState
private enum InitStep {
WAITING_ON_CLIENT_VERSION,
WAITING_ON_UNSIGNED_REFUND,
WAITING_ON_CONTRACT,
WAITING_ON_MULTISIG_ACCEPTANCE,
CHANNEL_OPEN
}
@GuardedBy("lock")
private InitStep step = InitStep.WAITING_ON_CLIENT_VERSION;
/**
* Implements the connection between this server and the client, providing an interface which
* allows messages to be sent to the client, requests for the connection to the client to be
* closed, and callbacks which occur when the channel is fully open or the client completes a
* payment.
*/
public interface ServerConnection {
/**
* Requests that the given message be sent to the client. There are no blocking requirements for
* this method, however the order of messages must be preserved.
*
* <p>If the send fails, no exception should be thrown, however {@link
* PaymentChannelServer#connectionClosed()} should be called immediately.
*
* <p>Called while holding a lock on the {@link PaymentChannelServer} object - be careful about
* reentrancy
*/
public void sendToClient(Protos.TwoWayChannelMessage msg);
/**
* Requests that the connection to the client be closed
*
* <p>Called while holding a lock on the {@link PaymentChannelServer} object - be careful about
* reentrancy
*
* @param reason The reason for the closure, see the individual values for more details. It is
* usually safe to ignore this value.
*/
public void destroyConnection(CloseReason reason);
/**
* Triggered when the channel is opened and payments can begin
*
* <p>Called while holding a lock on the {@link PaymentChannelServer} object - be careful about
* reentrancy
*
* @param contractHash A unique identifier which represents this channel (actually the hash of
* the multisig contract)
*/
public void channelOpen(Sha256Hash contractHash);
/**
* Called when the payment in this channel was successfully incremented by the client
*
* <p>Called while holding a lock on the {@link PaymentChannelServer} object - be careful about
* reentrancy
*
* @param by The increase in total payment
* @param to The new total payment to us (not including fees which may be required to claim the
* payment)
* @param info Information about this payment increase, used to extend this protocol.
* @return A future that completes with the ack message that will be included in the PaymentAck
* message to the client. Use null for no ack message.
*/
@Nullable
public ListenableFuture<ByteString> paymentIncrease(
Coin by, Coin to, @Nullable ByteString info);
}
private final ServerConnection conn;
// Used to keep track of whether or not the "socket" ie connection is open and we can generate
// messages
@GuardedBy("lock")
private boolean connectionOpen = false;
// Indicates that no further messages should be sent and we intend to settle the connection
@GuardedBy("lock")
private boolean channelSettling = false;
// The wallet and peergroup which are used to complete/broadcast transactions
private final Wallet wallet;
private final TransactionBroadcaster broadcaster;
// The key used for multisig in this channel
@GuardedBy("lock")
private ECKey myKey;
// The minimum accepted channel value
private final Coin minAcceptedChannelSize;
// The state manager for this channel
@GuardedBy("lock")
private PaymentChannelServerState state;
// The time this channel expires (ie the refund transaction's locktime)
@GuardedBy("lock")
private long expireTime;
public static final long DEFAULT_MAX_TIME_WINDOW = 7 * 24 * 60 * 60;
/**
* Maximum channel duration, in seconds, that the client can request. Defaults to 1 week. Note
* that the server needs to be online for the whole time the channel is open. Failure to do this
* could cause loss of all payments received on the channel.
*/
protected final long maxTimeWindow;
public static final long DEFAULT_MIN_TIME_WINDOW = 4 * 60 * 60;
public static final long HARD_MIN_TIME_WINDOW =
-StoredPaymentChannelServerStates.CHANNEL_EXPIRE_OFFSET;
/**
* Minimum channel duration, in seconds, that the client can request. Should always be larger than
* than 2 hours, defaults to 4 hours
*/
protected final long minTimeWindow;
/**
* Creates a new server-side state manager which handles a single client connection. The server
* will only accept a channel with time window between 4 hours and 1 week. Note that the server
* need to be online for the whole time the channel is open. Failure to do this could cause loss
* of all payments received on the channel.
*
* @param broadcaster The PeerGroup on which transactions will be broadcast - should have multiple
* connections.
* @param wallet The wallet which will be used to complete transactions. Unlike {@link
* PaymentChannelClient}, this does not have to already contain a StoredState manager
* @param minAcceptedChannelSize The minimum value the client must lock into this channel. A value
* too large will be rejected by clients, and a value too low will require excessive channel
* reopening and may cause fees to be require to settle the channel. A reasonable value
* depends entirely on the expected maximum for the channel, and should likely be somewhere
* between a few bitcents and a bitcoin.
* @param conn A callback listener which represents the connection to the client (forwards
* messages we generate to the client and will close the connection on request)
*/
public PaymentChannelServer(
TransactionBroadcaster broadcaster,
Wallet wallet,
Coin minAcceptedChannelSize,
ServerConnection conn) {
this(
broadcaster,
wallet,
minAcceptedChannelSize,
DEFAULT_MIN_TIME_WINDOW,
DEFAULT_MAX_TIME_WINDOW,
conn);
}
/**
* Creates a new server-side state manager which handles a single client connection.
*
* @param broadcaster The PeerGroup on which transactions will be broadcast - should have multiple
* connections.
* @param wallet The wallet which will be used to complete transactions. Unlike {@link
* PaymentChannelClient}, this does not have to already contain a StoredState manager
* @param minAcceptedChannelSize The minimum value the client must lock into this channel. A value
* too large will be rejected by clients, and a value too low will require excessive channel
* reopening and may cause fees to be require to settle the channel. A reasonable value
* depends entirely on the expected maximum for the channel, and should likely be somewhere
* between a few bitcents and a bitcoin.
* @param minTimeWindow The minimum allowed channel time window in seconds, must be larger than
* 7200.
* @param maxTimeWindow The maximum allowed channel time window in seconds. Note that the server
* need to be online for the whole time the channel is open. Failure to do this could cause
* loss of all payments received on the channel.
* @param conn A callback listener which represents the connection to the client (forwards
* messages we generate to the client and will close the connection on request)
*/
public PaymentChannelServer(
TransactionBroadcaster broadcaster,
Wallet wallet,
Coin minAcceptedChannelSize,
long minTimeWindow,
long maxTimeWindow,
ServerConnection conn) {
if (minTimeWindow > maxTimeWindow)
throw new IllegalArgumentException("minTimeWindow must be less or equal to maxTimeWindow");
if (minTimeWindow < HARD_MIN_TIME_WINDOW)
throw new IllegalArgumentException(
"minTimeWindow must be larger than" + HARD_MIN_TIME_WINDOW + " seconds");
this.broadcaster = checkNotNull(broadcaster);
this.wallet = checkNotNull(wallet);
this.minAcceptedChannelSize = checkNotNull(minAcceptedChannelSize);
this.conn = checkNotNull(conn);
this.minTimeWindow = minTimeWindow;
this.maxTimeWindow = maxTimeWindow;
}
/**
* Returns the underlying {@link PaymentChannelServerState} object that is being manipulated. This
* object allows you to learn how much money has been transferred, etc. May be null if the channel
* wasn't negotiated yet.
*/
@Nullable
public PaymentChannelServerState state() {
return state;
}
@GuardedBy("lock")
private void receiveVersionMessage(Protos.TwoWayChannelMessage msg) throws VerificationException {
checkState(step == InitStep.WAITING_ON_CLIENT_VERSION && msg.hasClientVersion());
final Protos.ClientVersion clientVersion = msg.getClientVersion();
final int major = clientVersion.getMajor();
if (major != SERVER_MAJOR_VERSION) {
error(
"This server needs protocol version "
+ SERVER_MAJOR_VERSION
+ " , client offered "
+ major,
Protos.Error.ErrorCode.NO_ACCEPTABLE_VERSION,
CloseReason.NO_ACCEPTABLE_VERSION);
return;
}
Protos.ServerVersion.Builder versionNegotiationBuilder =
Protos.ServerVersion.newBuilder()
.setMajor(SERVER_MAJOR_VERSION)
.setMinor(SERVER_MINOR_VERSION);
conn.sendToClient(
Protos.TwoWayChannelMessage.newBuilder()
.setType(Protos.TwoWayChannelMessage.MessageType.SERVER_VERSION)
.setServerVersion(versionNegotiationBuilder)
.build());
ByteString reopenChannelContractHash = clientVersion.getPreviousChannelContractHash();
if (reopenChannelContractHash != null && reopenChannelContractHash.size() == 32) {
Sha256Hash contractHash = new Sha256Hash(reopenChannelContractHash.toByteArray());
log.info("New client that wants to resume {}", contractHash);
StoredPaymentChannelServerStates channels =
(StoredPaymentChannelServerStates)
wallet.getExtensions().get(StoredPaymentChannelServerStates.EXTENSION_ID);
if (channels != null) {
StoredServerChannel storedServerChannel = channels.getChannel(contractHash);
if (storedServerChannel != null) {
final PaymentChannelServer existingHandler =
storedServerChannel.setConnectedHandler(this, false);
if (existingHandler != this) {
log.warn(" ... and that channel is already in use, disconnecting other user.");
existingHandler.close();
storedServerChannel.setConnectedHandler(this, true);
}
log.info("Got resume version message, responding with VERSIONS and CHANNEL_OPEN");
state = storedServerChannel.getOrCreateState(wallet, broadcaster);
step = InitStep.CHANNEL_OPEN;
conn.sendToClient(
Protos.TwoWayChannelMessage.newBuilder()
.setType(Protos.TwoWayChannelMessage.MessageType.CHANNEL_OPEN)
.build());
conn.channelOpen(contractHash);
return;
} else {
log.error(" ... but we do not have any record of that contract! Resume failed.");
}
} else {
log.error(" ... but we do not have any stored channels! Resume failed.");
}
}
log.info(
"Got initial version message, responding with VERSIONS and INITIATE: min value={}",
minAcceptedChannelSize.value);
myKey = new ECKey();
wallet.freshReceiveKey();
expireTime = Utils.currentTimeSeconds() + truncateTimeWindow(clientVersion.getTimeWindowSecs());
step = InitStep.WAITING_ON_UNSIGNED_REFUND;
Protos.Initiate.Builder initiateBuilder =
Protos.Initiate.newBuilder()
.setMultisigKey(ByteString.copyFrom(myKey.getPubKey()))
.setExpireTimeSecs(expireTime)
.setMinAcceptedChannelSize(minAcceptedChannelSize.value)
.setMinPayment(Transaction.REFERENCE_DEFAULT_MIN_TX_FEE.value);
conn.sendToClient(
Protos.TwoWayChannelMessage.newBuilder()
.setInitiate(initiateBuilder)
.setType(Protos.TwoWayChannelMessage.MessageType.INITIATE)
.build());
}
private long truncateTimeWindow(long timeWindow) {
if (timeWindow < minTimeWindow) {
log.info(
"client requested time window {} s to short, offering {} s", timeWindow, minTimeWindow);
return minTimeWindow;
}
if (timeWindow > maxTimeWindow) {
log.info(
"client requested time window {} s to long, offering {} s", timeWindow, minTimeWindow);
return maxTimeWindow;
}
return timeWindow;
}
@GuardedBy("lock")
private void receiveRefundMessage(Protos.TwoWayChannelMessage msg) throws VerificationException {
checkState(step == InitStep.WAITING_ON_UNSIGNED_REFUND && msg.hasProvideRefund());
log.info("Got refund transaction, returning signature");
Protos.ProvideRefund providedRefund = msg.getProvideRefund();
state = new PaymentChannelServerState(broadcaster, wallet, myKey, expireTime);
byte[] signature =
state.provideRefundTransaction(
new Transaction(wallet.getParams(), providedRefund.getTx().toByteArray()),
providedRefund.getMultisigKey().toByteArray());
step = InitStep.WAITING_ON_CONTRACT;
Protos.ReturnRefund.Builder returnRefundBuilder =
Protos.ReturnRefund.newBuilder().setSignature(ByteString.copyFrom(signature));
conn.sendToClient(
Protos.TwoWayChannelMessage.newBuilder()
.setReturnRefund(returnRefundBuilder)
.setType(Protos.TwoWayChannelMessage.MessageType.RETURN_REFUND)
.build());
}
private void multisigContractPropogated(
Protos.ProvideContract providedContract, Sha256Hash contractHash) {
lock.lock();
try {
if (!connectionOpen || channelSettling) return;
state.storeChannelInWallet(PaymentChannelServer.this);
try {
receiveUpdatePaymentMessage(providedContract.getInitialPayment(), false /* no ack msg */);
} catch (VerificationException e) {
log.error("Initial payment failed to verify", e);
error(
e.getMessage(),
Protos.Error.ErrorCode.BAD_TRANSACTION,
CloseReason.REMOTE_SENT_INVALID_MESSAGE);
return;
} catch (ValueOutOfRangeException e) {
log.error("Initial payment value was out of range", e);
error(
e.getMessage(),
Protos.Error.ErrorCode.BAD_TRANSACTION,
CloseReason.REMOTE_SENT_INVALID_MESSAGE);
return;
} catch (InsufficientMoneyException e) {
// This shouldn't happen because the server shouldn't allow itself to get into this
// situation in the
// first place, by specifying a min up front payment.
log.error(
"Tried to settle channel and could not afford the fees whilst updating payment", e);
error(
e.getMessage(),
Protos.Error.ErrorCode.BAD_TRANSACTION,
CloseReason.REMOTE_SENT_INVALID_MESSAGE);
return;
}
conn.sendToClient(
Protos.TwoWayChannelMessage.newBuilder()
.setType(Protos.TwoWayChannelMessage.MessageType.CHANNEL_OPEN)
.build());
step = InitStep.CHANNEL_OPEN;
conn.channelOpen(contractHash);
} finally {
lock.unlock();
}
}
@GuardedBy("lock")
private void receiveContractMessage(Protos.TwoWayChannelMessage msg)
throws VerificationException {
checkState(step == InitStep.WAITING_ON_CONTRACT && msg.hasProvideContract());
log.info("Got contract, broadcasting and responding with CHANNEL_OPEN");
final Protos.ProvideContract providedContract = msg.getProvideContract();
// TODO notify connection handler that timeout should be significantly extended as we wait for
// network propagation?
final Transaction multisigContract =
new Transaction(wallet.getParams(), providedContract.getTx().toByteArray());
step = InitStep.WAITING_ON_MULTISIG_ACCEPTANCE;
state
.provideMultiSigContract(multisigContract)
.addListener(
new Runnable() {
@Override
public void run() {
multisigContractPropogated(providedContract, multisigContract.getHash());
}
},
Threading.SAME_THREAD);
}
@GuardedBy("lock")
private void receiveUpdatePaymentMessage(Protos.UpdatePayment msg, boolean sendAck)
throws VerificationException, ValueOutOfRangeException, InsufficientMoneyException {
log.info("Got a payment update");
Coin lastBestPayment = state.getBestValueToMe();
final Coin refundSize = Coin.valueOf(msg.getClientChangeValue());
boolean stillUsable = state.incrementPayment(refundSize, msg.getSignature().toByteArray());
Coin bestPaymentChange = state.getBestValueToMe().subtract(lastBestPayment);
ListenableFuture<ByteString> ackInfoFuture = null;
if (bestPaymentChange.signum() > 0) {
ByteString info = (msg.hasInfo()) ? msg.getInfo() : null;
ackInfoFuture = conn.paymentIncrease(bestPaymentChange, state.getBestValueToMe(), info);
}
if (sendAck) {
final Protos.TwoWayChannelMessage.Builder ack = Protos.TwoWayChannelMessage.newBuilder();
ack.setType(Protos.TwoWayChannelMessage.MessageType.PAYMENT_ACK);
if (ackInfoFuture == null) {
conn.sendToClient(ack.build());
} else {
Futures.addCallback(
ackInfoFuture,
new FutureCallback<ByteString>() {
@Override
public void onSuccess(@Nullable ByteString result) {
if (result != null) ack.setPaymentAck(ack.getPaymentAckBuilder().setInfo(result));
conn.sendToClient(ack.build());
}
@Override
public void onFailure(Throwable t) {
log.info("Failed retrieving paymentIncrease info future");
error(
"Failed processing payment update",
Protos.Error.ErrorCode.OTHER,
CloseReason.UPDATE_PAYMENT_FAILED);
}
});
}
}
if (!stillUsable) {
log.info("Channel is now fully exhausted, closing/initiating settlement");
settlePayment(CloseReason.CHANNEL_EXHAUSTED);
}
}
/**
* Called when a message is received from the client. Processes the given message and generates
* events based on its content.
*/
public void receiveMessage(Protos.TwoWayChannelMessage msg) {
lock.lock();
try {
checkState(connectionOpen);
if (channelSettling) return;
// If we generate an error, we set errorBuilder and closeReason and break, otherwise we return
Protos.Error.Builder errorBuilder;
CloseReason closeReason;
try {
switch (msg.getType()) {
case CLIENT_VERSION:
receiveVersionMessage(msg);
return;
case PROVIDE_REFUND:
receiveRefundMessage(msg);
return;
case PROVIDE_CONTRACT:
receiveContractMessage(msg);
return;
case UPDATE_PAYMENT:
checkState(step == InitStep.CHANNEL_OPEN && msg.hasUpdatePayment());
receiveUpdatePaymentMessage(msg.getUpdatePayment(), true);
return;
case CLOSE:
receiveCloseMessage();
return;
case ERROR:
checkState(msg.hasError());
log.error(
"Client sent ERROR {} with explanation {}",
msg.getError().getCode().name(),
msg.getError().hasExplanation() ? msg.getError().getExplanation() : "");
conn.destroyConnection(CloseReason.REMOTE_SENT_ERROR);
return;
default:
final String errorText =
"Got unknown message type or type that doesn't apply to servers.";
error(
errorText,
Protos.Error.ErrorCode.SYNTAX_ERROR,
CloseReason.REMOTE_SENT_INVALID_MESSAGE);
}
} catch (VerificationException e) {
log.error("Caught verification exception handling message from client", e);
error(
e.getMessage(),
Protos.Error.ErrorCode.BAD_TRANSACTION,
CloseReason.REMOTE_SENT_INVALID_MESSAGE);
} catch (ValueOutOfRangeException e) {
log.error("Caught value out of range exception handling message from client", e);
error(
e.getMessage(),
Protos.Error.ErrorCode.BAD_TRANSACTION,
CloseReason.REMOTE_SENT_INVALID_MESSAGE);
} catch (InsufficientMoneyException e) {
log.error("Caught insufficient money exception handling message from client", e);
error(
e.getMessage(),
Protos.Error.ErrorCode.BAD_TRANSACTION,
CloseReason.REMOTE_SENT_INVALID_MESSAGE);
} catch (IllegalStateException e) {
log.error("Caught illegal state exception handling message from client", e);
error(
e.getMessage(),
Protos.Error.ErrorCode.SYNTAX_ERROR,
CloseReason.REMOTE_SENT_INVALID_MESSAGE);
}
} finally {
lock.unlock();
}
}
private void error(String message, Protos.Error.ErrorCode errorCode, CloseReason closeReason) {
log.error(message);
Protos.Error.Builder errorBuilder;
errorBuilder = Protos.Error.newBuilder().setCode(errorCode).setExplanation(message);
conn.sendToClient(
Protos.TwoWayChannelMessage.newBuilder()
.setError(errorBuilder)
.setType(Protos.TwoWayChannelMessage.MessageType.ERROR)
.build());
conn.destroyConnection(closeReason);
}
@GuardedBy("lock")
private void receiveCloseMessage() throws InsufficientMoneyException {
log.info("Got CLOSE message, closing channel");
if (state != null) {
settlePayment(CloseReason.CLIENT_REQUESTED_CLOSE);
} else {
conn.destroyConnection(CloseReason.CLIENT_REQUESTED_CLOSE);
}
}
@GuardedBy("lock")
private void settlePayment(final CloseReason clientRequestedClose)
throws InsufficientMoneyException {
// Setting channelSettling here prevents us from sending another CLOSE when state.close() calls
// close() on us here below via the stored channel state.
// TODO: Strongly separate the lifecycle of the payment channel from the TCP connection in these
// classes.
channelSettling = true;
Futures.addCallback(
state.close(),
new FutureCallback<Transaction>() {
@Override
public void onSuccess(Transaction result) {
// Send the successfully accepted transaction back to the client.
final Protos.TwoWayChannelMessage.Builder msg =
Protos.TwoWayChannelMessage.newBuilder();
msg.setType(Protos.TwoWayChannelMessage.MessageType.CLOSE);
if (result != null) {
// Result can be null on various error paths, like if we never actually opened
// properly and so on.
msg.getSettlementBuilder().setTx(ByteString.copyFrom(result.peercoinSerialize()));
log.info("Sending CLOSE back with broadcast settlement tx.");
} else {
log.info("Sending CLOSE back without broadcast settlement tx.");
}
conn.sendToClient(msg.build());
conn.destroyConnection(clientRequestedClose);
}
@Override
public void onFailure(Throwable t) {
log.error("Failed to broadcast settlement tx", t);
conn.destroyConnection(clientRequestedClose);
}
});
}
/**
* Called when the connection terminates. Notifies the {@link StoredServerChannel} object that we
* can attempt to resume this channel in the future and stops generating messages for the client.
*
* <p>Note that this <b>MUST</b> still be called even after either {@link
* ServerConnection#destroyConnection(CloseReason)} or {@link PaymentChannelServer#close()} is
* called to actually handle the connection close logic.
*/
public void connectionClosed() {
lock.lock();
try {
log.info("Server channel closed.");
connectionOpen = false;
try {
if (state != null && state.getMultisigContract() != null) {
StoredPaymentChannelServerStates channels =
(StoredPaymentChannelServerStates)
wallet.getExtensions().get(StoredPaymentChannelServerStates.EXTENSION_ID);
if (channels != null) {
StoredServerChannel storedServerChannel =
channels.getChannel(state.getMultisigContract().getHash());
if (storedServerChannel != null) {
storedServerChannel.clearConnectedHandler();
}
}
}
} catch (IllegalStateException e) {
// Expected when we call getMultisigContract() sometimes
}
} finally {
lock.unlock();
}
}
/**
* Called to indicate the connection has been opened and messages can now be generated for the
* client.
*/
public void connectionOpen() {
lock.lock();
try {
log.info("New server channel active.");
connectionOpen = true;
} finally {
lock.unlock();
}
}
/**
* Closes the connection by generating a settle message for the client and calls {@link
* ServerConnection#destroyConnection(CloseReason)}. Note that this does not broadcast the payment
* transaction and the client may still resume the same channel if they reconnect
*
* <p>
*
* <p>Note that {@link PaymentChannelServer#connectionClosed()} must still be called after the
* connection fully closes.
*/
public void close() {
lock.lock();
try {
if (connectionOpen && !channelSettling) {
final Protos.TwoWayChannelMessage.Builder msg = Protos.TwoWayChannelMessage.newBuilder();
msg.setType(Protos.TwoWayChannelMessage.MessageType.CLOSE);
conn.sendToClient(msg.build());
conn.destroyConnection(CloseReason.SERVER_REQUESTED_CLOSE);
}
} finally {
lock.unlock();
}
}
}