public async Task DisposeAsync() { List <Task> disposing = new List <Task>(); if (Invoice != null) { disposing.Add(_invoiceRepository.AddInvoiceLogs(Invoice.Id, Logs)); } if (!doNotBroadcast && OriginalTransaction != null) { disposing.Add(_explorerClient.BroadcastAsync(OriginalTransaction)); } if (!success && LockedUTXOs != null) { disposing.Add(_payJoinRepository.TryUnlock(LockedUTXOs)); } try { await Task.WhenAll(disposing); } catch (Exception ex) { BTCPayServer.Logging.Logs.PayServer.LogWarning(ex, "Error while disposing the PayjoinReceiverContext"); } }
public async Task <IActionResult> Submit(string cryptoCode) { var network = _btcPayNetworkProvider.GetNetwork <BTCPayNetwork>(cryptoCode); if (network == null) { return(BadRequest(CreatePayjoinError(400, "invalid-network", "Incorrect network"))); } var explorer = _explorerClientProvider.GetExplorerClient(network); if (Request.ContentLength is long length) { if (length > 1_000_000) { return(this.StatusCode(413, CreatePayjoinError(413, "payload-too-large", "The transaction is too big to be processed"))); } } else { return(StatusCode(411, CreatePayjoinError(411, "missing-content-length", "The http header Content-Length should be filled"))); } string rawBody; using (StreamReader reader = new StreamReader(Request.Body, Encoding.UTF8)) { rawBody = (await reader.ReadToEndAsync()) ?? string.Empty; } Transaction originalTx = null; FeeRate originalFeeRate = null; bool psbtFormat = true; if (!PSBT.TryParse(rawBody, network.NBitcoinNetwork, out var psbt)) { psbtFormat = false; if (!Transaction.TryParse(rawBody, network.NBitcoinNetwork, out var tx)) { return(BadRequest(CreatePayjoinError(400, "invalid-format", "invalid transaction or psbt"))); } originalTx = tx; psbt = PSBT.FromTransaction(tx, network.NBitcoinNetwork); psbt = (await explorer.UpdatePSBTAsync(new UpdatePSBTRequest() { PSBT = psbt })).PSBT; for (int i = 0; i < tx.Inputs.Count; i++) { psbt.Inputs[i].FinalScriptSig = tx.Inputs[i].ScriptSig; psbt.Inputs[i].FinalScriptWitness = tx.Inputs[i].WitScript; } } else { if (!psbt.IsAllFinalized()) { return(BadRequest(CreatePayjoinError(400, "psbt-not-finalized", "The PSBT should be finalized"))); } originalTx = psbt.ExtractTransaction(); } async Task BroadcastNow() { await _explorerClientProvider.GetExplorerClient(network).BroadcastAsync(originalTx); } var sendersInputType = psbt.GetInputsScriptPubKeyType(); if (sendersInputType is null) { return(BadRequest(CreatePayjoinError(400, "unsupported-inputs", "Payjoin only support segwit inputs (of the same type)"))); } if (psbt.CheckSanity() is var errors && errors.Count != 0) { return(BadRequest(CreatePayjoinError(400, "insane-psbt", $"This PSBT is insane ({errors[0]})"))); } if (!psbt.TryGetEstimatedFeeRate(out originalFeeRate)) { return(BadRequest(CreatePayjoinError(400, "need-utxo-information", "You need to provide Witness UTXO information to the PSBT."))); } // This is actually not a mandatory check, but we don't want implementers // to leak global xpubs if (psbt.GlobalXPubs.Any()) { return(BadRequest(CreatePayjoinError(400, "leaking-data", "GlobalXPubs should not be included in the PSBT"))); } if (psbt.Outputs.Any(o => o.HDKeyPaths.Count != 0) || psbt.Inputs.Any(o => o.HDKeyPaths.Count != 0)) { return(BadRequest(CreatePayjoinError(400, "leaking-data", "Keypath information should not be included in the PSBT"))); } if (psbt.Inputs.Any(o => !o.IsFinalized())) { return(BadRequest(CreatePayjoinError(400, "psbt-not-finalized", "The PSBT Should be finalized"))); } //////////// var mempool = await explorer.BroadcastAsync(originalTx, true); if (!mempool.Success) { return(BadRequest(CreatePayjoinError(400, "invalid-transaction", $"Provided transaction isn't mempool eligible {mempool.RPCCodeMessage}"))); } var paymentMethodId = new PaymentMethodId(network.CryptoCode, PaymentTypes.BTCLike); bool paidSomething = false; Money due = null; Dictionary <OutPoint, UTXO> selectedUTXOs = new Dictionary <OutPoint, UTXO>(); async Task UnlockUTXOs() { await _payJoinRepository.TryUnlock(selectedUTXOs.Select(o => o.Key).ToArray()); } PSBTOutput originalPaymentOutput = null; BitcoinAddress paymentAddress = null; InvoiceEntity invoice = null; DerivationSchemeSettings derivationSchemeSettings = null; foreach (var output in psbt.Outputs) { var key = output.ScriptPubKey.Hash + "#" + network.CryptoCode.ToUpperInvariant(); invoice = (await _invoiceRepository.GetInvoicesFromAddresses(new[] { key })).FirstOrDefault(); if (invoice is null) { continue; } derivationSchemeSettings = invoice.GetSupportedPaymentMethod <DerivationSchemeSettings>(paymentMethodId) .SingleOrDefault(); if (derivationSchemeSettings is null) { continue; } var receiverInputsType = derivationSchemeSettings.AccountDerivation.ScriptPubKeyType(); if (!PayjoinClient.SupportedFormats.Contains(receiverInputsType)) { //this should never happen, unless the store owner changed the wallet mid way through an invoice return(StatusCode(500, CreatePayjoinError(500, "unavailable", $"This service is unavailable for now"))); } if (sendersInputType != receiverInputsType) { return(StatusCode(503, CreatePayjoinError(503, "out-of-utxos", "We do not have any UTXO available for making a payjoin with the sender's inputs type"))); } var paymentMethod = invoice.GetPaymentMethod(paymentMethodId); var paymentDetails = paymentMethod.GetPaymentMethodDetails() as Payments.Bitcoin.BitcoinLikeOnChainPaymentMethod; if (paymentDetails is null || !paymentDetails.PayjoinEnabled) { continue; } if (invoice.GetAllBitcoinPaymentData().Any()) { return(UnprocessableEntity(CreatePayjoinError(422, "already-paid", $"The invoice this PSBT is paying has already been partially or completely paid"))); } paidSomething = true; due = paymentMethod.Calculate().TotalDue - output.Value; if (due > Money.Zero) { break; } if (!await _payJoinRepository.TryLockInputs(originalTx.Inputs.Select(i => i.PrevOut).ToArray())) { return(BadRequest(CreatePayjoinError(400, "inputs-already-used", "Some of those inputs have already been used to make payjoin transaction"))); } var utxos = (await explorer.GetUTXOsAsync(derivationSchemeSettings.AccountDerivation)) .GetUnspentUTXOs(false); // In case we are paying ourselves, be need to make sure // we can't take spent outpoints. var prevOuts = originalTx.Inputs.Select(o => o.PrevOut).ToHashSet(); utxos = utxos.Where(u => !prevOuts.Contains(u.Outpoint)).ToArray(); Array.Sort(utxos, UTXODeterministicComparer.Instance); foreach (var utxo in await SelectUTXO(network, utxos, output.Value, psbt.Outputs.Where(o => o.Index != output.Index).Select(o => o.Value).ToArray())) { selectedUTXOs.Add(utxo.Outpoint, utxo); } originalPaymentOutput = output; paymentAddress = paymentDetails.GetDepositAddress(network.NBitcoinNetwork); break; } if (!paidSomething) { return(BadRequest(CreatePayjoinError(400, "invoice-not-found", "This transaction does not pay any invoice with payjoin"))); } if (due is null || due > Money.Zero) { return(BadRequest(CreatePayjoinError(400, "invoice-not-fully-paid", "The transaction must pay the whole invoice"))); } if (selectedUTXOs.Count == 0) { await BroadcastNow(); return(StatusCode(503, CreatePayjoinError(503, "out-of-utxos", "We do not have any UTXO available for making a payjoin for now"))); } var originalPaymentValue = originalPaymentOutput.Value; await _broadcaster.Schedule(DateTimeOffset.UtcNow + TimeSpan.FromMinutes(1.0), originalTx, network); //check if wallet of store is configured to be hot wallet var extKeyStr = await explorer.GetMetadataAsync <string>( derivationSchemeSettings.AccountDerivation, WellknownMetadataKeys.AccountHDKey); if (extKeyStr == null) { // This should not happen, as we check the existance of private key before creating invoice with payjoin await UnlockUTXOs(); await BroadcastNow(); return(StatusCode(500, CreatePayjoinError(500, "unavailable", $"This service is unavailable for now"))); } Money contributedAmount = Money.Zero; var newTx = originalTx.Clone(); var ourNewOutput = newTx.Outputs[originalPaymentOutput.Index]; HashSet <TxOut> isOurOutput = new HashSet <TxOut>(); isOurOutput.Add(ourNewOutput); foreach (var selectedUTXO in selectedUTXOs.Select(o => o.Value)) { contributedAmount += (Money)selectedUTXO.Value; newTx.Inputs.Add(selectedUTXO.Outpoint); } ourNewOutput.Value += contributedAmount; var minRelayTxFee = this._dashboard.Get(network.CryptoCode).Status.BitcoinStatus?.MinRelayTxFee ?? new FeeRate(1.0m); // Probably receiving some spare change, let's add an output to make // it looks more like a normal transaction if (newTx.Outputs.Count == 1) { var change = await explorer.GetUnusedAsync(derivationSchemeSettings.AccountDerivation, DerivationFeature.Change); var randomChangeAmount = RandomUtils.GetUInt64() % (ulong)contributedAmount.Satoshi; // Randomly round the amount to make the payment output look like a change output var roundMultiple = (ulong)Math.Pow(10, (ulong)Math.Log10(randomChangeAmount)); while (roundMultiple > 1_000UL) { if (RandomUtils.GetUInt32() % 2 == 0) { roundMultiple = roundMultiple / 10; } else { randomChangeAmount = (randomChangeAmount / roundMultiple) * roundMultiple; break; } } var fakeChange = newTx.Outputs.CreateNewTxOut(randomChangeAmount, change.ScriptPubKey); if (fakeChange.IsDust(minRelayTxFee)) { randomChangeAmount = fakeChange.GetDustThreshold(minRelayTxFee); fakeChange.Value = randomChangeAmount; } if (randomChangeAmount < contributedAmount) { ourNewOutput.Value -= fakeChange.Value; newTx.Outputs.Add(fakeChange); isOurOutput.Add(fakeChange); } } var rand = new Random(); Utils.Shuffle(newTx.Inputs, rand); Utils.Shuffle(newTx.Outputs, rand); // Remove old signatures as they are not valid anymore foreach (var input in newTx.Inputs) { input.WitScript = WitScript.Empty; } Money ourFeeContribution = Money.Zero; // We need to adjust the fee to keep a constant fee rate var txBuilder = network.NBitcoinNetwork.CreateTransactionBuilder(); txBuilder.AddCoins(psbt.Inputs.Select(i => i.GetSignableCoin())); txBuilder.AddCoins(selectedUTXOs.Select(o => o.Value.AsCoin(derivationSchemeSettings.AccountDerivation))); Money expectedFee = txBuilder.EstimateFees(newTx, originalFeeRate); Money actualFee = newTx.GetFee(txBuilder.FindSpentCoins(newTx)); Money additionalFee = expectedFee - actualFee; if (additionalFee > Money.Zero) { // If the user overpaid, taking fee on our output (useful if sender dump a full UTXO for privacy) for (int i = 0; i < newTx.Outputs.Count && additionalFee > Money.Zero && due < Money.Zero; i++) { if (isOurOutput.Contains(newTx.Outputs[i])) { var outputContribution = Money.Min(additionalFee, -due); outputContribution = Money.Min(outputContribution, newTx.Outputs[i].Value - newTx.Outputs[i].GetDustThreshold(minRelayTxFee)); newTx.Outputs[i].Value -= outputContribution; additionalFee -= outputContribution; due += outputContribution; ourFeeContribution += outputContribution; } } // The rest, we take from user's change for (int i = 0; i < newTx.Outputs.Count && additionalFee > Money.Zero; i++) { if (!isOurOutput.Contains(newTx.Outputs[i])) { var outputContribution = Money.Min(additionalFee, newTx.Outputs[i].Value); outputContribution = Money.Min(outputContribution, newTx.Outputs[i].Value - newTx.Outputs[i].GetDustThreshold(minRelayTxFee)); newTx.Outputs[i].Value -= outputContribution; additionalFee -= outputContribution; } } if (additionalFee > Money.Zero) { // We could not pay fully the additional fee, however, as long as // we are not under the relay fee, it should be OK. var newVSize = txBuilder.EstimateSize(newTx, true); var newFeePaid = newTx.GetFee(txBuilder.FindSpentCoins(newTx)); if (new FeeRate(newFeePaid, newVSize) < minRelayTxFee) { await UnlockUTXOs(); await BroadcastNow(); return(UnprocessableEntity(CreatePayjoinError(422, "not-enough-money", "Not enough money is sent to pay for the additional payjoin inputs"))); } } } var accountKey = ExtKey.Parse(extKeyStr, network.NBitcoinNetwork); var newPsbt = PSBT.FromTransaction(newTx, network.NBitcoinNetwork); foreach (var selectedUtxo in selectedUTXOs.Select(o => o.Value)) { var signedInput = newPsbt.Inputs.FindIndexedInput(selectedUtxo.Outpoint); var coin = selectedUtxo.AsCoin(derivationSchemeSettings.AccountDerivation); signedInput.UpdateFromCoin(coin); var privateKey = accountKey.Derive(selectedUtxo.KeyPath).PrivateKey; signedInput.Sign(privateKey); signedInput.FinalizeInput(); newTx.Inputs[signedInput.Index].WitScript = newPsbt.Inputs[(int)signedInput.Index].FinalScriptWitness; } // Add the transaction to the payments with a confirmation of -1. // This will make the invoice paid even if the user do not // broadcast the payjoin. var originalPaymentData = new BitcoinLikePaymentData(paymentAddress, originalPaymentOutput.Value, new OutPoint(originalTx.GetHash(), originalPaymentOutput.Index), originalTx.RBF); originalPaymentData.ConfirmationCount = -1; originalPaymentData.PayjoinInformation = new PayjoinInformation() { CoinjoinTransactionHash = newPsbt.GetGlobalTransaction().GetHash(), CoinjoinValue = originalPaymentValue - ourFeeContribution, ContributedOutPoints = selectedUTXOs.Select(o => o.Key).ToArray() }; var payment = await _invoiceRepository.AddPayment(invoice.Id, DateTimeOffset.UtcNow, originalPaymentData, network, true); if (payment is null) { await UnlockUTXOs(); await BroadcastNow(); return(UnprocessableEntity(CreatePayjoinError(422, "already-paid", $"The original transaction has already been accounted"))); } await _btcPayWalletProvider.GetWallet(network).SaveOffchainTransactionAsync(originalTx); _eventAggregator.Publish(new InvoiceEvent(invoice, 1002, InvoiceEvent.ReceivedPayment) { Payment = payment }); if (psbtFormat && HexEncoder.IsWellFormed(rawBody)) { return(Ok(newPsbt.ToHex())); } else if (psbtFormat) { return(Ok(newPsbt.ToBase64())); } else { return(Ok(newTx.ToHex())); } }