/**
* Updates the outputs on the payment contract transaction and re-signs it. The state must be
* READY in order to call this method. The signature that is returned should be sent to the server
* so it has the ability to broadcast the best seen payment when the channel closes or times out.
*
* <p>The returned signature is over the payment transaction, which we never have a valid copy of
* and thus there is no accessor for it on this object.
*
* <p>To spend the whole channel increment by {@link PaymentChannelClientState#getTotalValue()} -
* {@link PaymentChannelClientState#getValueRefunded()}
*
* @param size How many satoshis to increment the payment by (note: not the new total).
* @throws ValueOutOfRangeException If size is negative or the channel does not have sufficient
* money in it to complete this payment.
*/
public synchronized IncrementedPayment incrementPaymentBy(Coin size)
throws ValueOutOfRangeException {
checkState(state == State.READY);
checkNotExpired();
checkNotNull(size); // Validity of size will be checked by makeUnsignedChannelContract.
if (size.signum() < 0) throw new ValueOutOfRangeException("Tried to decrement payment");
Coin newValueToMe = valueToMe.subtract(size);
if (newValueToMe.compareTo(Transaction.MIN_NONDUST_OUTPUT) < 0 && newValueToMe.signum() > 0) {
log.info(
"New value being sent back as change was smaller than minimum nondust output, sending all");
size = valueToMe;
newValueToMe = Coin.ZERO;
}
if (newValueToMe.signum() < 0)
throw new ValueOutOfRangeException(
"Channel has too little money to pay " + size + " satoshis");
Transaction tx = makeUnsignedChannelContract(newValueToMe);
log.info("Signing new payment tx {}", tx);
Transaction.SigHash mode;
// If we spent all the money we put into this channel, we (by definition) don't care what the
// outputs are, so
// we sign with SIGHASH_NONE to let the server do what it wants.
if (newValueToMe.equals(Coin.ZERO)) mode = Transaction.SigHash.NONE;
else mode = Transaction.SigHash.SINGLE;
TransactionSignature sig = tx.calculateSignature(0, myKey, multisigScript, mode, true);
valueToMe = newValueToMe;
updateChannelInWallet();
IncrementedPayment payment = new IncrementedPayment();
payment.signature = sig;
payment.amount = size;
return payment;
}
/**
* Creates a state object for a payment channel client. It is expected that you be ready to {@link
* PaymentChannelClientState#initiate()} after construction (to avoid creating objects for
* channels which are not going to finish opening) and thus some parameters provided here are only
* used in {@link PaymentChannelClientState#initiate()} to create the Multisig contract and refund
* transaction.
*
* @param wallet a wallet that contains at least the specified amount of value.
* @param myKey a freshly generated private key for this channel.
* @param serverMultisigKey a public key retrieved from the server used for the initial multisig
* contract
* @param value how many satoshis to put into this contract. If the channel reaches this limit, it
* must be closed. It is suggested you use at least {@link Utils#CENT} to avoid paying fees if
* you need to spend the refund transaction
* @param expiryTimeInSeconds At what point (UNIX timestamp +/- a few hours) the channel will
* expire
* @throws VerificationException If either myKey's pubkey or serverMultisigKey's pubkey are
* non-canonical (ie invalid)
*/
public PaymentChannelClientState(
Wallet wallet, ECKey myKey, ECKey serverMultisigKey, Coin value, long expiryTimeInSeconds)
throws VerificationException {
checkArgument(value.signum() > 0);
this.wallet = checkNotNull(wallet);
initWalletListeners();
this.serverMultisigKey = checkNotNull(serverMultisigKey);
this.myKey = checkNotNull(myKey);
this.valueToMe = this.totalValue = checkNotNull(value);
this.expiryTime = expiryTimeInSeconds;
this.state = State.NEW;
}
public TransactionOutput(
NetworkParameters params, @Nullable Transaction parent, Coin value, byte[] scriptBytes) {
super(params);
// Negative values obviously make no sense, except for -1 which is used as a sentinel value when
// calculating
// SIGHASH_SINGLE signatures, so unfortunately we have to allow that here.
checkArgument(
value.signum() >= 0 || value.equals(Coin.NEGATIVE_SATOSHI), "Negative values not allowed");
checkArgument(
value.compareTo(NetworkParameters.MAX_MONEY) < 0,
"Values larger than MAX_MONEY not allowed");
this.value = value.value;
this.scriptBytes = scriptBytes;
parentTransaction = parent;
availableForSpending = true;
length = 8 + VarInt.sizeOf(scriptBytes.length) + scriptBytes.length;
}
/**
* Called when the client provides us with a new signature and wishes to increment total payment
* by size. Verifies the provided signature and only updates values if everything checks out. If
* the new refundSize is not the lowest we have seen, it is simply ignored.
*
* @param refundSize How many satoshis of the original contract are refunded to the client (the
* rest are ours)
* @param signatureBytes The new signature spending the multi-sig contract to a new payment
* transaction
* @throws VerificationException If the signature does not verify or size is out of range (incl
* being rejected by the network as dust).
* @return true if there is more value left on the channel, false if it is now fully used up.
*/
public synchronized boolean incrementPayment(Coin refundSize, byte[] signatureBytes)
throws VerificationException, ValueOutOfRangeException, InsufficientMoneyException {
checkState(state == State.READY);
checkNotNull(refundSize);
checkNotNull(signatureBytes);
TransactionSignature signature = TransactionSignature.decodeFromBitcoin(signatureBytes, true);
// We allow snapping to zero for the payment amount because it's treated specially later, but
// not less than
// the dust level because that would prevent the transaction from being relayed/mined.
final boolean fullyUsedUp = refundSize.equals(Coin.ZERO);
if (refundSize.compareTo(clientOutput.getMinNonDustValue()) < 0 && !fullyUsedUp)
throw new ValueOutOfRangeException(
"Attempt to refund negative value or value too small to be accepted by the network");
Coin newValueToMe = totalValue.subtract(refundSize);
if (newValueToMe.signum() < 0)
throw new ValueOutOfRangeException("Attempt to refund more than the contract allows.");
if (newValueToMe.compareTo(bestValueToMe) < 0)
throw new ValueOutOfRangeException("Attempt to roll back payment on the channel.");
// Get the wallet's copy of the multisigContract (ie with confidence information), if this is
// null, the wallet
// was not connected to the peergroup when the contract was broadcast (which may cause issues
// down the road, and
// disables our double-spend check next)
Transaction walletContract = wallet.getTransaction(multisigContract.getHash());
checkNotNull(
walletContract,
"Wallet did not contain multisig contract {} after state was marked READY",
multisigContract.getHash());
// Note that we check for DEAD state here, but this test is essentially useless in production
// because we will
// miss most double-spends due to bloom filtering right now anyway. This will eventually fixed
// by network-wide
// double-spend notifications, so we just wait instead of attempting to add all dependant
// outpoints to our bloom
// filters (and probably missing lots of edge-cases).
if (walletContract.getConfidence().getConfidenceType()
== TransactionConfidence.ConfidenceType.DEAD) {
close();
throw new VerificationException("Multisig contract was double-spent");
}
Transaction.SigHash mode;
// If the client doesn't want anything back, they shouldn't sign any outputs at all.
if (fullyUsedUp) mode = Transaction.SigHash.NONE;
else mode = Transaction.SigHash.SINGLE;
if (signature.sigHashMode() != mode || !signature.anyoneCanPay())
throw new VerificationException(
"New payment signature was not signed with the right SIGHASH flags.");
Wallet.SendRequest req = makeUnsignedChannelContract(newValueToMe);
// Now check the signature is correct.
// Note that the client must sign with SIGHASH_{SINGLE/NONE} | SIGHASH_ANYONECANPAY to allow us
// to add additional
// inputs (in case we need to add significant fee, or something...) and any outputs we want to
// pay to.
Sha256Hash sighash = req.tx.hashForSignature(0, multisigScript, mode, true);
if (!clientKey.verify(sighash, signature))
throw new VerificationException("Signature does not verify on tx\n" + req.tx);
bestValueToMe = newValueToMe;
bestValueSignature = signatureBytes;
updateChannelInWallet();
return !fullyUsedUp;
}
@Override
/** Used during reorgs to connect a block previously on a fork */
protected synchronized TransactionOutputChanges connectTransactions(StoredBlock newBlock)
throws VerificationException, BlockStoreException, PrunedException {
checkState(lock.isHeldByCurrentThread());
if (!params.passesCheckpoint(newBlock.getHeight(), newBlock.getHeader().getHash()))
throw new VerificationException("Block failed checkpoint lockin at " + newBlock.getHeight());
blockStore.beginDatabaseBatchWrite();
StoredUndoableBlock block = blockStore.getUndoBlock(newBlock.getHeader().getHash());
if (block == null) {
// We're trying to re-org too deep and the data needed has been deleted.
blockStore.abortDatabaseBatchWrite();
throw new PrunedException(newBlock.getHeader().getHash());
}
TransactionOutputChanges txOutChanges;
try {
List<Transaction> transactions = block.getTransactions();
if (transactions != null) {
LinkedList<StoredTransactionOutput> txOutsSpent = new LinkedList<StoredTransactionOutput>();
LinkedList<StoredTransactionOutput> txOutsCreated =
new LinkedList<StoredTransactionOutput>();
long sigOps = 0;
final boolean enforcePayToScriptHash =
newBlock.getHeader().getTimeSeconds() >= NetworkParameters.BIP16_ENFORCE_TIME;
if (!params.isCheckpoint(newBlock.getHeight())) {
for (Transaction tx : transactions) {
Sha256Hash hash = tx.getHash();
if (blockStore.hasUnspentOutputs(hash, tx.getOutputs().size()))
throw new VerificationException("Block failed BIP30 test!");
}
}
Coin totalFees = Coin.ZERO;
Coin coinbaseValue = null;
if (scriptVerificationExecutor.isShutdown())
scriptVerificationExecutor =
Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
List<Future<VerificationException>> listScriptVerificationResults =
new ArrayList<Future<VerificationException>>(transactions.size());
for (final Transaction tx : transactions) {
boolean isCoinBase = tx.isCoinBase();
Coin valueIn = Coin.ZERO;
Coin valueOut = Coin.ZERO;
final List<Script> prevOutScripts = new LinkedList<Script>();
if (!isCoinBase) {
for (int index = 0; index < tx.getInputs().size(); index++) {
final TransactionInput in = tx.getInputs().get(index);
final StoredTransactionOutput prevOut =
blockStore.getTransactionOutput(
in.getOutpoint().getHash(), in.getOutpoint().getIndex());
if (prevOut == null)
throw new VerificationException(
"Attempted spend of a non-existent or already spent output!");
if (newBlock.getHeight() - prevOut.getHeight() < params.getSpendableCoinbaseDepth())
throw new VerificationException(
"Tried to spend coinbase at depth "
+ (newBlock.getHeight() - prevOut.getHeight()));
valueIn = valueIn.add(prevOut.getValue());
if (enforcePayToScriptHash) {
Script script = new Script(prevOut.getScriptBytes());
if (script.isPayToScriptHash())
sigOps += Script.getP2SHSigOpCount(in.getScriptBytes());
if (sigOps > Block.MAX_BLOCK_SIGOPS)
throw new VerificationException("Too many P2SH SigOps in block");
}
prevOutScripts.add(new Script(prevOut.getScriptBytes()));
blockStore.removeUnspentTransactionOutput(prevOut);
txOutsSpent.add(prevOut);
}
}
Sha256Hash hash = tx.getHash();
for (TransactionOutput out : tx.getOutputs()) {
valueOut = valueOut.add(out.getValue());
StoredTransactionOutput newOut =
new StoredTransactionOutput(
hash,
out.getIndex(),
out.getValue(),
newBlock.getHeight(),
isCoinBase,
out.getScriptBytes());
blockStore.addUnspentTransactionOutput(newOut);
txOutsCreated.add(newOut);
}
// All values were already checked for being non-negative (as it is verified in
// Transaction.verify())
// but we check again here just for defence in depth. Transactions with zero output value
// are OK.
if (valueOut.signum() < 0 || valueOut.compareTo(NetworkParameters.MAX_MONEY) > 0)
throw new VerificationException("Transaction output value out of range");
if (isCoinBase) {
coinbaseValue = valueOut;
} else {
if (valueIn.compareTo(valueOut) < 0
|| valueIn.compareTo(NetworkParameters.MAX_MONEY) > 0)
throw new VerificationException("Transaction input value out of range");
totalFees = totalFees.add(valueIn.subtract(valueOut));
}
if (!isCoinBase) {
// Because correctlySpends modifies transactions, this must come after we are done with
// tx
FutureTask<VerificationException> future =
new FutureTask<VerificationException>(
new Verifier(tx, prevOutScripts, enforcePayToScriptHash));
scriptVerificationExecutor.execute(future);
listScriptVerificationResults.add(future);
}
}
if (totalFees.compareTo(NetworkParameters.MAX_MONEY) > 0
|| newBlock
.getHeader()
.getBlockInflation(newBlock.getHeight())
.add(totalFees)
.compareTo(coinbaseValue)
< 0) throw new VerificationException("Transaction fees out of range");
txOutChanges = new TransactionOutputChanges(txOutsCreated, txOutsSpent);
for (Future<VerificationException> future : listScriptVerificationResults) {
VerificationException e;
try {
e = future.get();
} catch (InterruptedException thrownE) {
throw new RuntimeException(thrownE); // Shouldn't happen
} catch (ExecutionException thrownE) {
log.error("Script.correctlySpends threw a non-normal exception: " + thrownE.getCause());
throw new VerificationException(
"Bug in Script.correctlySpends, likely script malformed in some new and interesting way.",
thrownE);
}
if (e != null) throw e;
}
} else {
txOutChanges = block.getTxOutChanges();
if (!params.isCheckpoint(newBlock.getHeight()))
for (StoredTransactionOutput out : txOutChanges.txOutsCreated) {
Sha256Hash hash = out.getHash();
if (blockStore.getTransactionOutput(hash, out.getIndex()) != null)
throw new VerificationException("Block failed BIP30 test!");
}
for (StoredTransactionOutput out : txOutChanges.txOutsCreated)
blockStore.addUnspentTransactionOutput(out);
for (StoredTransactionOutput out : txOutChanges.txOutsSpent)
blockStore.removeUnspentTransactionOutput(out);
}
} catch (VerificationException e) {
scriptVerificationExecutor.shutdownNow();
blockStore.abortDatabaseBatchWrite();
throw e;
} catch (BlockStoreException e) {
scriptVerificationExecutor.shutdownNow();
blockStore.abortDatabaseBatchWrite();
throw e;
}
return txOutChanges;
}
@Override
protected TransactionOutputChanges connectTransactions(int height, Block block)
throws VerificationException, BlockStoreException {
checkState(lock.isHeldByCurrentThread());
if (block.transactions == null)
throw new RuntimeException(
"connectTransactions called with Block that didn't have transactions!");
if (!params.passesCheckpoint(height, block.getHash()))
throw new VerificationException("Block failed checkpoint lockin at " + height);
blockStore.beginDatabaseBatchWrite();
LinkedList<StoredTransactionOutput> txOutsSpent = new LinkedList<StoredTransactionOutput>();
LinkedList<StoredTransactionOutput> txOutsCreated = new LinkedList<StoredTransactionOutput>();
long sigOps = 0;
final boolean enforcePayToScriptHash =
block.getTimeSeconds() >= NetworkParameters.BIP16_ENFORCE_TIME;
if (scriptVerificationExecutor.isShutdown())
scriptVerificationExecutor =
Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
List<Future<VerificationException>> listScriptVerificationResults =
new ArrayList<Future<VerificationException>>(block.transactions.size());
try {
if (!params.isCheckpoint(height)) {
// BIP30 violator blocks are ones that contain a duplicated transaction. They are all in the
// checkpoints list and we therefore only check non-checkpoints for duplicated transactions
// here. See the
// BIP30 document for more details on this:
// https://github.com/bitcoin/bips/blob/master/bip-0030.mediawiki
for (Transaction tx : block.transactions) {
Sha256Hash hash = tx.getHash();
// If we already have unspent outputs for this hash, we saw the tx already. Either the
// block is
// being added twice (bug) or the block is a BIP30 violator.
if (blockStore.hasUnspentOutputs(hash, tx.getOutputs().size()))
throw new VerificationException("Block failed BIP30 test!");
if (enforcePayToScriptHash) // We already check non-BIP16 sigops in
// Block.verifyTransactions(true)
sigOps += tx.getSigOpCount();
}
}
Coin totalFees = Coin.ZERO;
Coin coinbaseValue = null;
for (final Transaction tx : block.transactions) {
boolean isCoinBase = tx.isCoinBase();
Coin valueIn = Coin.ZERO;
Coin valueOut = Coin.ZERO;
final List<Script> prevOutScripts = new LinkedList<Script>();
if (!isCoinBase) {
// For each input of the transaction remove the corresponding output from the set of
// unspent
// outputs.
for (int index = 0; index < tx.getInputs().size(); index++) {
TransactionInput in = tx.getInputs().get(index);
StoredTransactionOutput prevOut =
blockStore.getTransactionOutput(
in.getOutpoint().getHash(), in.getOutpoint().getIndex());
if (prevOut == null)
throw new VerificationException(
"Attempted to spend a non-existent or already spent output!");
// Coinbases can't be spent until they mature, to avoid re-orgs destroying entire
// transaction
// chains. The assumption is there will ~never be re-orgs deeper than the spendable
// coinbase
// chain depth.
if (height - prevOut.getHeight() < params.getSpendableCoinbaseDepth())
throw new VerificationException(
"Tried to spend coinbase at depth " + (height - prevOut.getHeight()));
// TODO: Check we're not spending the genesis transaction here. Satoshis code won't
// allow it.
valueIn = valueIn.add(prevOut.getValue());
if (enforcePayToScriptHash) {
if (new Script(prevOut.getScriptBytes()).isPayToScriptHash())
sigOps += Script.getP2SHSigOpCount(in.getScriptBytes());
if (sigOps > Block.MAX_BLOCK_SIGOPS)
throw new VerificationException("Too many P2SH SigOps in block");
}
prevOutScripts.add(new Script(prevOut.getScriptBytes()));
// in.getScriptSig().correctlySpends(tx, index, new Script(params,
// prevOut.getScriptBytes(), 0, prevOut.getScriptBytes().length));
blockStore.removeUnspentTransactionOutput(prevOut);
txOutsSpent.add(prevOut);
}
}
Sha256Hash hash = tx.getHash();
for (TransactionOutput out : tx.getOutputs()) {
valueOut = valueOut.add(out.getValue());
// For each output, add it to the set of unspent outputs so it can be consumed in future.
StoredTransactionOutput newOut =
new StoredTransactionOutput(
hash, out.getIndex(), out.getValue(), height, isCoinBase, out.getScriptBytes());
blockStore.addUnspentTransactionOutput(newOut);
txOutsCreated.add(newOut);
}
// All values were already checked for being non-negative (as it is verified in
// Transaction.verify())
// but we check again here just for defence in depth. Transactions with zero output value
// are OK.
if (valueOut.signum() < 0 || valueOut.compareTo(NetworkParameters.MAX_MONEY) > 0)
throw new VerificationException("Transaction output value out of range");
if (isCoinBase) {
coinbaseValue = valueOut;
} else {
if (valueIn.compareTo(valueOut) < 0 || valueIn.compareTo(NetworkParameters.MAX_MONEY) > 0)
throw new VerificationException("Transaction input value out of range");
totalFees = totalFees.add(valueIn.subtract(valueOut));
}
if (!isCoinBase && runScripts) {
// Because correctlySpends modifies transactions, this must come after we are done with tx
FutureTask<VerificationException> future =
new FutureTask<VerificationException>(
new Verifier(tx, prevOutScripts, enforcePayToScriptHash));
scriptVerificationExecutor.execute(future);
listScriptVerificationResults.add(future);
}
}
if (totalFees.compareTo(NetworkParameters.MAX_MONEY) > 0
|| block.getBlockInflation(height).add(totalFees).compareTo(coinbaseValue) < 0)
throw new VerificationException("Transaction fees out of range");
for (Future<VerificationException> future : listScriptVerificationResults) {
VerificationException e;
try {
e = future.get();
} catch (InterruptedException thrownE) {
throw new RuntimeException(thrownE); // Shouldn't happen
} catch (ExecutionException thrownE) {
log.error("Script.correctlySpends threw a non-normal exception: " + thrownE.getCause());
throw new VerificationException(
"Bug in Script.correctlySpends, likely script malformed in some new and interesting way.",
thrownE);
}
if (e != null) throw e;
}
} catch (VerificationException e) {
scriptVerificationExecutor.shutdownNow();
blockStore.abortDatabaseBatchWrite();
throw e;
} catch (BlockStoreException e) {
scriptVerificationExecutor.shutdownNow();
blockStore.abortDatabaseBatchWrite();
throw e;
}
return new TransactionOutputChanges(txOutsCreated, txOutsSpent);
}
