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 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 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();
}
}
@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);
}
}
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();
}
}
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 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 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());
}
/**
* 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();
}
}
@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());
}