/*
* Copyright 2013 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.bitcoinj.protocols.channels;
import com.google.common.collect.ImmutableMap;
import org.bitcoinj.core.*;
import org.bitcoinj.utils.Threading;
import org.bitcoinj.wallet.Wallet;
import org.bitcoinj.wallet.WalletExtension;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.util.concurrent.SettableFuture;
import com.google.protobuf.ByteString;
import net.jcip.annotations.GuardedBy;
import org.slf4j.LoggerFactory;
import javax.annotation.Nullable;
import java.util.*;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.locks.ReentrantLock;
import static com.google.common.base.Preconditions.*;
/**
* Keeps track of a set of {@link StoredServerChannel}s and expires them 2 hours before their refund transactions
* unlock.
*/
public class StoredPaymentChannelServerStates implements WalletExtension {
private static final org.slf4j.Logger log = LoggerFactory.getLogger(StoredPaymentChannelServerStates.class);
static final String EXTENSION_ID = StoredPaymentChannelServerStates.class.getName();
static final int MAX_SECONDS_TO_WAIT_FOR_BROADCASTER_TO_BE_SET = 10;
@GuardedBy("lock") @VisibleForTesting final Map<Sha256Hash, StoredServerChannel> mapChannels = new HashMap<Sha256Hash, StoredServerChannel>();
private Wallet wallet;
private final SettableFuture<TransactionBroadcaster> broadcasterFuture = SettableFuture.create();
private final Timer channelTimeoutHandler = new Timer(true);
private final ReentrantLock lock = Threading.lock("StoredPaymentChannelServerStates");
/**
* The offset between the refund transaction's lock time and the time channels will be automatically closed.
* This defines a window during which we must get the last payment transaction verified, ie it should allow time for
* network propagation and for the payment transaction to be included in a block. Note that the channel expire time
* is measured in terms of our local clock, and the refund transaction's lock time is measured in terms of Bitcoin
* block header timestamps, which are allowed to drift up to two hours in the future, as measured by relaying nodes.
*/
public static final long CHANNEL_EXPIRE_OFFSET = -2*60*60;
/**
* Creates a new PaymentChannelServerStateManager and associates it with the given {@link Wallet} and
* {@link TransactionBroadcaster} which are used to complete and announce payment transactions.
*/
public StoredPaymentChannelServerStates(@Nullable Wallet wallet, TransactionBroadcaster broadcaster) {
setTransactionBroadcaster(broadcaster);
this.wallet = wallet;
}
/**
* Creates a new PaymentChannelServerStateManager and associates it with the given {@link Wallet}
*
* Use this constructor if you use WalletAppKit, it will provide the broadcaster for you (no need to call the setter)
*/
public StoredPaymentChannelServerStates(@Nullable Wallet wallet) {
this.wallet = wallet;
}
/**
* Use this setter if the broadcaster is not available during instantiation and you're not using WalletAppKit.
* This setter will let you delay the setting of the broadcaster until the Bitcoin network is ready.
*
* @param broadcaster Used when the payment channels are closed
*/
public final void setTransactionBroadcaster(TransactionBroadcaster broadcaster) {
this.broadcasterFuture.set(checkNotNull(broadcaster));
}
/** Returns this extension from the given wallet, or null if no such extension was added. */
@Nullable
public static StoredPaymentChannelServerStates getFromWallet(Wallet wallet) {
return (StoredPaymentChannelServerStates) wallet.getExtensions().get(EXTENSION_ID);
}
/**
* <p>Closes the given channel using {@link ServerConnectionEventHandler#closeChannel()} and
* {@link PaymentChannelV1ServerState#close()} to notify any connected client of channel closure and to complete and
* broadcast the latest payment transaction.</p>
*
* <p>Removes the given channel from this set of {@link StoredServerChannel}s and notifies the wallet of a change to
* this wallet extension.</p>
*/
public void closeChannel(StoredServerChannel channel) {
lock.lock();
try {
if (mapChannels.remove(channel.contract.getHash()) == null)
return;
} finally {
lock.unlock();
}
synchronized (channel) {
channel.closeConnectedHandler();
try {
TransactionBroadcaster broadcaster = getBroadcaster();
channel.getOrCreateState(wallet, broadcaster).close();
} catch (InsufficientMoneyException e) {
log.error("Exception when closing channel", e);
} catch (VerificationException e) {
log.error("Exception when closing channel", e);
}
channel.state = null;
}
updatedChannel(channel);
}
/**
* If the broadcaster has not been set for MAX_SECONDS_TO_WAIT_FOR_BROADCASTER_TO_BE_SET seconds, then
* the programmer probably forgot to set it and we should throw exception.
*/
private TransactionBroadcaster getBroadcaster() {
try {
return broadcasterFuture.get(MAX_SECONDS_TO_WAIT_FOR_BROADCASTER_TO_BE_SET, TimeUnit.SECONDS);
} catch (InterruptedException e) {
throw new RuntimeException(e);
} catch (ExecutionException e) {
throw new RuntimeException(e);
} catch (TimeoutException e) {
String err = "Transaction broadcaster not set";
log.error(err);
throw new RuntimeException(err,e);
}
}
/**
* Gets the {@link StoredServerChannel} with the given channel id (ie contract transaction hash).
*/
public StoredServerChannel getChannel(Sha256Hash id) {
lock.lock();
try {
return mapChannels.get(id);
} finally {
lock.unlock();
}
}
/**
* Get a copy of all {@link StoredServerChannel}s
*/
public Map<Sha256Hash, StoredServerChannel> getChannelMap() {
lock.lock();
try {
return ImmutableMap.copyOf(mapChannels);
} finally {
lock.unlock();
}
}
/**
* Notifies the set of stored states that a channel has been updated. Use to notify the wallet of an update to this
* wallet extension.
*/
public void updatedChannel(final StoredServerChannel channel) {
log.info("Stored server channel {} was updated", channel.hashCode());
wallet.addOrUpdateExtension(this);
}
/**
* <p>Puts the given channel in the channels map and automatically closes it 2 hours before its refund transaction
* becomes spendable.</p>
*
* <p>Because there must be only one, canonical {@link StoredServerChannel} per channel, this method throws if the
* channel is already present in the set of channels.</p>
*/
public void putChannel(final StoredServerChannel channel) {
lock.lock();
try {
checkArgument(mapChannels.put(channel.contract.getHash(), checkNotNull(channel)) == null);
// Add the difference between real time and Utils.now() so that test-cases can use a mock clock.
Date autocloseTime = new Date((channel.refundTransactionUnlockTimeSecs + CHANNEL_EXPIRE_OFFSET) * 1000L
+ (System.currentTimeMillis() - Utils.currentTimeMillis()));
log.info("Scheduling channel for automatic closure at {}: {}", autocloseTime, channel);
channelTimeoutHandler.schedule(new TimerTask() {
@Override
public void run() {
log.info("Auto-closing channel: {}", channel);
try {
closeChannel(channel);
} catch (Exception e) {
// Something went wrong closing the channel - we catch
// here or else we take down the whole Timer.
log.error("Auto-closing channel failed", e);
}
}
}, autocloseTime);
} finally {
lock.unlock();
}
updatedChannel(channel);
}
@Override
public String getWalletExtensionID() {
return EXTENSION_ID;
}
@Override
public boolean isWalletExtensionMandatory() {
return false;
}
@Override
public byte[] serializeWalletExtension() {
lock.lock();
try {
final NetworkParameters params = getNetworkParameters();
// If we haven't attached to a wallet yet we can't check against network parameters
final boolean hasMaxMoney = params != null ? params.hasMaxMoney() : true;
final Coin networkMaxMoney = params != null ? params.getMaxMoney() : NetworkParameters.MAX_MONEY;
ServerState.StoredServerPaymentChannels.Builder builder = ServerState.StoredServerPaymentChannels.newBuilder();
for (StoredServerChannel channel : mapChannels.values()) {
// First a few asserts to make sure things won't break
// TODO: Pull MAX_MONEY from network parameters
checkState(channel.bestValueToMe.signum() >= 0 &&
(!hasMaxMoney || channel.bestValueToMe.compareTo(networkMaxMoney) <= 0));
checkState(channel.refundTransactionUnlockTimeSecs > 0);
checkNotNull(channel.myKey.getPrivKeyBytes());
ServerState.StoredServerPaymentChannel.Builder channelBuilder = ServerState.StoredServerPaymentChannel.newBuilder()
.setMajorVersion(channel.majorVersion)
.setBestValueToMe(channel.bestValueToMe.value)
.setRefundTransactionUnlockTimeSecs(channel.refundTransactionUnlockTimeSecs)
.setContractTransaction(ByteString.copyFrom(channel.contract.unsafeBitcoinSerialize()))
.setMyKey(ByteString.copyFrom(channel.myKey.getPrivKeyBytes()));
if (channel.majorVersion == 1) {
channelBuilder.setClientOutput(ByteString.copyFrom(channel.clientOutput.unsafeBitcoinSerialize()));
} else {
channelBuilder.setClientKey(ByteString.copyFrom(channel.clientKey.getPubKey()));
}
if (channel.bestValueSignature != null)
channelBuilder.setBestValueSignature(ByteString.copyFrom(channel.bestValueSignature));
builder.addChannels(channelBuilder);
}
return builder.build().toByteArray();
} finally {
lock.unlock();
}
}
@Override
public void deserializeWalletExtension(Wallet containingWallet, byte[] data) throws Exception {
lock.lock();
try {
this.wallet = containingWallet;
ServerState.StoredServerPaymentChannels states = ServerState.StoredServerPaymentChannels.parseFrom(data);
NetworkParameters params = containingWallet.getParams();
for (ServerState.StoredServerPaymentChannel storedState : states.getChannelsList()) {
final int majorVersion = storedState.getMajorVersion();
TransactionOutput clientOutput = null;
ECKey clientKey = null;
if (majorVersion == 1) {
clientOutput = new TransactionOutput(params, null, storedState.getClientOutput().toByteArray(), 0);
} else {
clientKey = ECKey.fromPublicOnly(storedState.getClientKey().toByteArray());
}
StoredServerChannel channel = new StoredServerChannel(null,
majorVersion,
params.getDefaultSerializer().makeTransaction(storedState.getContractTransaction().toByteArray()),
clientOutput,
storedState.getRefundTransactionUnlockTimeSecs(),
ECKey.fromPrivate(storedState.getMyKey().toByteArray()),
clientKey,
Coin.valueOf(storedState.getBestValueToMe()),
storedState.hasBestValueSignature() ? storedState.getBestValueSignature().toByteArray() : null);
putChannel(channel);
}
} finally {
lock.unlock();
}
}
@Override
public String toString() {
lock.lock();
try {
StringBuilder buf = new StringBuilder();
for (StoredServerChannel stored : mapChannels.values()) {
buf.append(stored);
}
return buf.toString();
} finally {
lock.unlock();
}
}
private @Nullable NetworkParameters getNetworkParameters() {
return wallet != null ? wallet.getNetworkParameters() : null;
}
}