/*
* 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.ImmutableMultimap;
import com.google.common.collect.Multimap;
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.collect.HashMultimap;
import com.google.common.util.concurrent.SettableFuture;
import com.google.protobuf.ByteString;
import net.jcip.annotations.GuardedBy;
import org.slf4j.Logger;
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.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
/**
* This class maintains a set of {@link StoredClientChannel}s, automatically (re)broadcasting the contract transaction
* and broadcasting the refund transaction over the given {@link TransactionBroadcaster}.
*/
public class StoredPaymentChannelClientStates implements WalletExtension {
private static final Logger log = LoggerFactory.getLogger(StoredPaymentChannelClientStates.class);
static final String EXTENSION_ID = StoredPaymentChannelClientStates.class.getName();
static final int MAX_SECONDS_TO_WAIT_FOR_BROADCASTER_TO_BE_SET = 10;
@GuardedBy("lock") @VisibleForTesting final HashMultimap<Sha256Hash, StoredClientChannel> mapChannels = HashMultimap.create();
@VisibleForTesting final Timer channelTimeoutHandler = new Timer(true);
private Wallet containingWallet;
private final SettableFuture<TransactionBroadcaster> announcePeerGroupFuture = SettableFuture.create();
protected final ReentrantLock lock = Threading.lock("StoredPaymentChannelClientStates");
/**
* Creates a new StoredPaymentChannelClientStates and associates it with the given {@link Wallet} and
* {@link TransactionBroadcaster} which are used to complete and announce contract and refund
* transactions.
*/
public StoredPaymentChannelClientStates(@Nullable Wallet containingWallet, TransactionBroadcaster announcePeerGroup) {
setTransactionBroadcaster(announcePeerGroup);
this.containingWallet = containingWallet;
}
/**
* Creates a new StoredPaymentChannelClientStates 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 StoredPaymentChannelClientStates(@Nullable Wallet containingWallet) {
this.containingWallet = containingWallet;
}
/**
* 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 transactionBroadcaster which is used to complete and announce contract and refund transactions.
*/
public final void setTransactionBroadcaster(TransactionBroadcaster transactionBroadcaster) {
this.announcePeerGroupFuture.set(checkNotNull(transactionBroadcaster));
}
/** Returns this extension from the given wallet, or null if no such extension was added. */
@Nullable
public static StoredPaymentChannelClientStates getFromWallet(Wallet wallet) {
return (StoredPaymentChannelClientStates) wallet.getExtensions().get(EXTENSION_ID);
}
/** Returns the outstanding amount of money sent back to us for all channels to this server added together. */
public Coin getBalanceForServer(Sha256Hash id) {
Coin balance = Coin.ZERO;
lock.lock();
try {
Set<StoredClientChannel> setChannels = mapChannels.get(id);
for (StoredClientChannel channel : setChannels) {
synchronized (channel) {
if (channel.close != null) continue;
balance = balance.add(channel.valueToMe);
}
}
return balance;
} finally {
lock.unlock();
}
}
/**
* Returns the number of seconds from now until this servers next channel will expire, or zero if no unexpired
* channels found.
*/
public long getSecondsUntilExpiry(Sha256Hash id) {
lock.lock();
try {
final Set<StoredClientChannel> setChannels = mapChannels.get(id);
final long nowSeconds = Utils.currentTimeSeconds();
int earliestTime = Integer.MAX_VALUE;
for (StoredClientChannel channel : setChannels) {
synchronized (channel) {
if (channel.expiryTimeSeconds() > nowSeconds)
earliestTime = Math.min(earliestTime, (int) channel.expiryTimeSeconds());
}
}
return earliestTime == Integer.MAX_VALUE ? 0 : earliestTime - nowSeconds;
} finally {
lock.unlock();
}
}
/**
* Finds an inactive channel with the given id and returns it, or returns null.
*/
@Nullable
StoredClientChannel getUsableChannelForServerID(Sha256Hash id) {
lock.lock();
try {
Set<StoredClientChannel> setChannels = mapChannels.get(id);
for (StoredClientChannel channel : setChannels) {
synchronized (channel) {
// Check if the channel is usable (has money, inactive) and if so, activate it.
log.info("Considering channel {} contract {}", channel.hashCode(), channel.contract.getHash());
if (channel.close != null || channel.valueToMe.equals(Coin.ZERO)) {
log.info(" ... but is closed or empty");
continue;
}
if (!channel.active) {
log.info(" ... activating");
channel.active = true;
return channel;
}
log.info(" ... but is already active");
}
}
} finally {
lock.unlock();
}
return null;
}
/**
* Finds a channel with the given id and contract hash and returns it, or returns null.
*/
@Nullable
public StoredClientChannel getChannel(Sha256Hash id, Sha256Hash contractHash) {
lock.lock();
try {
Set<StoredClientChannel> setChannels = mapChannels.get(id);
for (StoredClientChannel channel : setChannels) {
if (channel.contract.getHash().equals(contractHash))
return channel;
}
return null;
} finally {
lock.unlock();
}
}
/**
* Get a copy of all {@link StoredClientChannel}s
*/
public Multimap<Sha256Hash, StoredClientChannel> getChannelMap() {
lock.lock();
try {
return ImmutableMultimap.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.
*/
void updatedChannel(final StoredClientChannel channel) {
log.info("Stored client channel {} was updated", channel.hashCode());
containingWallet.addOrUpdateExtension(this);
}
/**
* Adds the given channel to this set of stored states, broadcasting the contract and refund transactions when the
* channel expires and notifies the wallet of an update to this wallet extension
*/
void putChannel(final StoredClientChannel channel) {
putChannel(channel, true);
}
// Adds this channel and optionally notifies the wallet of an update to this extension (used during deserialize)
private void putChannel(final StoredClientChannel channel, boolean updateWallet) {
lock.lock();
try {
mapChannels.put(channel.id, channel);
channelTimeoutHandler.schedule(new TimerTask() {
@Override
public void run() {
try {
TransactionBroadcaster announcePeerGroup = getAnnouncePeerGroup();
removeChannel(channel);
announcePeerGroup.broadcastTransaction(channel.contract);
announcePeerGroup.broadcastTransaction(channel.refund);
} 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);
}
}
// Add the difference between real time and Utils.now() so that test-cases can use a mock clock.
}, new Date(channel.expiryTimeSeconds() * 1000 + (System.currentTimeMillis() - Utils.currentTimeMillis())));
} finally {
lock.unlock();
}
if (updateWallet)
updatedChannel(channel);
}
/**
* If the peer group 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 getAnnouncePeerGroup() {
try {
return announcePeerGroupFuture.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);
}
}
/**
* <p>Removes the channel with the given id from this set of stored states and notifies the wallet of an update to
* this wallet extension.</p>
*
* <p>Note that the channel will still have its contract and refund transactions broadcast via the connected
* {@link TransactionBroadcaster} as long as this {@link StoredPaymentChannelClientStates} continues to
* exist in memory.</p>
*/
void removeChannel(StoredClientChannel channel) {
lock.lock();
try {
mapChannels.remove(channel.id, channel);
} 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;
ClientState.StoredClientPaymentChannels.Builder builder = ClientState.StoredClientPaymentChannels.newBuilder();
for (StoredClientChannel channel : mapChannels.values()) {
// First a few asserts to make sure things won't break
checkState(channel.valueToMe.signum() >= 0 &&
(!hasMaxMoney || channel.valueToMe.compareTo(networkMaxMoney) <= 0));
checkState(channel.refundFees.signum() >= 0 &&
(!hasMaxMoney || channel.refundFees.compareTo(networkMaxMoney) <= 0));
checkNotNull(channel.myKey.getPubKey());
checkState(channel.refund.getConfidence().getSource() == TransactionConfidence.Source.SELF);
checkNotNull(channel.myKey.getPubKey());
final ClientState.StoredClientPaymentChannel.Builder value = ClientState.StoredClientPaymentChannel.newBuilder()
.setMajorVersion(channel.majorVersion)
.setId(ByteString.copyFrom(channel.id.getBytes()))
.setContractTransaction(ByteString.copyFrom(channel.contract.unsafeBitcoinSerialize()))
.setRefundFees(channel.refundFees.value)
.setRefundTransaction(ByteString.copyFrom(channel.refund.unsafeBitcoinSerialize()))
.setMyKey(ByteString.copyFrom(new byte[0])) // Not used, but protobuf message requires
.setMyPublicKey(ByteString.copyFrom(channel.myKey.getPubKey()))
.setServerKey(ByteString.copyFrom(channel.serverKey.getPubKey()))
.setValueToMe(channel.valueToMe.value)
.setExpiryTime(channel.expiryTime);
if (channel.close != null)
value.setCloseTransactionHash(ByteString.copyFrom(channel.close.getHash().getBytes()));
builder.addChannels(value);
}
return builder.build().toByteArray();
} finally {
lock.unlock();
}
}
@Override
public void deserializeWalletExtension(Wallet containingWallet, byte[] data) throws Exception {
lock.lock();
try {
checkState(this.containingWallet == null || this.containingWallet == containingWallet);
this.containingWallet = containingWallet;
NetworkParameters params = containingWallet.getParams();
ClientState.StoredClientPaymentChannels states = ClientState.StoredClientPaymentChannels.parseFrom(data);
for (ClientState.StoredClientPaymentChannel storedState : states.getChannelsList()) {
Transaction refundTransaction = params.getDefaultSerializer().makeTransaction(storedState.getRefundTransaction().toByteArray());
refundTransaction.getConfidence().setSource(TransactionConfidence.Source.SELF);
ECKey myKey = (storedState.getMyKey().isEmpty()) ?
containingWallet.findKeyFromPubKey(storedState.getMyPublicKey().toByteArray()) :
ECKey.fromPrivate(storedState.getMyKey().toByteArray());
ECKey serverKey = storedState.hasServerKey() ? ECKey.fromPublicOnly(storedState.getServerKey().toByteArray()) : null;
StoredClientChannel channel = new StoredClientChannel(storedState.getMajorVersion(),
Sha256Hash.wrap(storedState.getId().toByteArray()),
params.getDefaultSerializer().makeTransaction(storedState.getContractTransaction().toByteArray()),
refundTransaction,
myKey,
serverKey,
Coin.valueOf(storedState.getValueToMe()),
Coin.valueOf(storedState.getRefundFees()),
storedState.getExpiryTime(),
false);
if (storedState.hasCloseTransactionHash()) {
Sha256Hash closeTxHash = Sha256Hash.wrap(storedState.getCloseTransactionHash().toByteArray());
channel.close = containingWallet.getTransaction(closeTxHash);
}
putChannel(channel, false);
}
} finally {
lock.unlock();
}
}
@Override
public String toString() {
lock.lock();
try {
StringBuilder buf = new StringBuilder("Client payment channel states:\n");
for (StoredClientChannel channel : mapChannels.values())
buf.append(" ").append(channel).append("\n");
return buf.toString();
} finally {
lock.unlock();
}
}
private @Nullable NetworkParameters getNetworkParameters() {
return this.containingWallet != null ? this.containingWallet.getNetworkParameters() : null;
}
}
/**
* Represents the state of a channel once it has been opened in such a way that it can be stored and used to resume a
* channel which was interrupted (eg on connection failure) or keep track of refund transactions which need broadcast
* when they expire.
*/
class StoredClientChannel {
int majorVersion;
Sha256Hash id;
Transaction contract, refund;
// The expiry time of the contract in protocol v2.
long expiryTime;
// The transaction that closed the channel (generated by the server)
Transaction close;
ECKey myKey;
ECKey serverKey;
Coin valueToMe, refundFees;
// In-memory flag to indicate intent to resume this channel (or that the channel is already in use)
boolean active = false;
StoredClientChannel(int majorVersion, Sha256Hash id, Transaction contract, Transaction refund, ECKey myKey, ECKey serverKey, Coin valueToMe,
Coin refundFees, long expiryTime, boolean active) {
this.majorVersion = majorVersion;
this.id = id;
this.contract = contract;
this.refund = refund;
this.myKey = myKey;
this.serverKey = serverKey;
this.valueToMe = valueToMe;
this.refundFees = refundFees;
this.expiryTime = expiryTime;
this.active = active;
}
long expiryTimeSeconds() {
switch (majorVersion) {
case 1:
return refund.getLockTime() + 60 * 5;
case 2:
return expiryTime + 60 * 5;
default:
throw new IllegalStateException("Invalid version");
}
}
@Override
public String toString() {
final String newline = String.format(Locale.US, "%n");
final String closeStr = close == null ? "still open" : close.toString().replaceAll(newline, newline + " ");
return String.format(Locale.US, "Stored client channel for server ID %s (%s)%n" +
" Version: %d%n" +
" Key: %s%n" +
" Server key: %s%n" +
" Value left: %s%n" +
" Refund fees: %s%n" +
" Expiry : %s%n" +
" Contract: %s" +
"Refund: %s" +
"Close: %s",
id, active ? "active" : "inactive", majorVersion, myKey, serverKey, valueToMe, refundFees, expiryTime,
contract.toString().replaceAll(newline, newline + " "),
refund.toString().replaceAll(newline, newline + " "),
closeStr);
}
}