Sweep deposits with extra data

The `Bridge` contract supports a new shape of the deposit script that allows
embedding arbitrary 32-byte extra data. Here we introduce necessary adjustments
in the wallet client to make it able to sweep those deposits.

pkg/chain/ethereum/tbtc.go

@@ -1111,13 +1111,19 @@ func (tc *TbtcChain) GetDepositRequest(
 		vault = &v
 	}
 
+	var extraData *[32]byte
+	if depositRequest.ExtraData != [32]byte{} {
+		extraData = &depositRequest.ExtraData
+	}
+
 	return &tbtc.DepositChainRequest{
 		Depositor:   chain.Address(depositRequest.Depositor.Hex()),
 		Amount:      depositRequest.Amount,
 		RevealedAt:  time.Unix(int64(depositRequest.RevealedAt), 0),
 		Vault:       vault,
 		TreasuryFee: depositRequest.TreasuryFee,
 		SweptAt:     time.Unix(int64(depositRequest.SweptAt), 0),
+		ExtraData:   extraData,
 	}, true, nil
 }
 

pkg/tbtc/chain.go

@@ -261,7 +261,7 @@ type DepositRevealedEvent struct {
 	BlockNumber         uint64
 }
 
-func (dre *DepositRevealedEvent) unpack() *Deposit {
+func (dre *DepositRevealedEvent) unpack(extraData *[32]byte) *Deposit {
 	return &Deposit{
 		Utxo: &bitcoin.UnspentTransactionOutput{
 			Outpoint: &bitcoin.TransactionOutpoint{
@@ -276,6 +276,7 @@ func (dre *DepositRevealedEvent) unpack() *Deposit {
 		RefundPublicKeyHash: dre.RefundPublicKeyHash,
 		RefundLocktime:      dre.RefundLocktime,
 		Vault:               dre.Vault,
+		ExtraData:           extraData,
 	}
 }
 
@@ -303,6 +304,7 @@ type DepositChainRequest struct {
 	Vault       *chain.Address
 	TreasuryFee uint64
 	SweptAt     time.Time
+	ExtraData   *[32]byte
 }
 
 // WalletChainData represents wallet data stored on-chain.

pkg/tbtc/chain_test.go

@@ -68,6 +68,9 @@ type localChain struct {
 	heartbeatProposalValidationsMutex sync.Mutex
 	heartbeatProposalValidations      map[[16]byte]bool
 
+	depositRequestsMutex sync.Mutex
+	depositRequests      map[[32]byte]*DepositChainRequest
+
 	blockCounter       chain.BlockCounter
 	operatorPrivateKey *operator.PrivateKey
 }
@@ -582,13 +585,6 @@ func (lc *localChain) GetPendingRedemptionRequest(
 	return request, true, nil
 }
 
-func (lc *localChain) GetDepositRequest(
-	fundingTxHash bitcoin.Hash,
-	fundingOutputIndex uint32,
-) (*DepositChainRequest, bool, error) {
-	panic("not supported")
-}
-
 func (lc *localChain) setPendingRedemptionRequest(
 	walletPublicKeyHash [20]byte,
 	request *RedemptionRequest,
@@ -611,6 +607,46 @@ func buildRedemptionRequestKey(
 	return sha256.Sum256(append(walletPublicKeyHash[:], redeemerOutputScript...))
 }
 
+func (lc *localChain) GetDepositRequest(
+	fundingTxHash bitcoin.Hash,
+	fundingOutputIndex uint32,
+) (*DepositChainRequest, bool, error) {
+	lc.depositRequestsMutex.Lock()
+	defer lc.depositRequestsMutex.Unlock()
+
+	requestKey := buildDepositRequestKey(fundingTxHash, fundingOutputIndex)
+
+	request, ok := lc.depositRequests[requestKey]
+	if !ok {
+		return nil, false, nil
+	}
+
+	return request, true, nil
+}
+
+func (lc *localChain) setDepositRequest(
+	fundingTxHash bitcoin.Hash,
+	fundingOutputIndex uint32,
+	request *DepositChainRequest,
+) {
+	lc.depositRequestsMutex.Lock()
+	defer lc.depositRequestsMutex.Unlock()
+
+	requestKey := buildDepositRequestKey(fundingTxHash, fundingOutputIndex)
+
+	lc.depositRequests[requestKey] = request
+}
+
+func buildDepositRequestKey(
+	fundingTxHash bitcoin.Hash,
+	fundingOutputIndex uint32,
+) [32]byte {
+	buffer := make([]byte, 4)
+	binary.BigEndian.PutUint32(buffer[:], fundingOutputIndex)
+
+	return sha256.Sum256(append(fundingTxHash[:], buffer...))
+}
+
 func (lc *localChain) GetWallet(walletPublicKeyHash [20]byte) (
 	*WalletChainData,
 	error,
@@ -891,6 +927,7 @@ func ConnectWithKey(
 		pendingRedemptionRequests:       make(map[[32]byte]*RedemptionRequest),
 		redemptionProposalValidations:   make(map[[32]byte]bool),
 		heartbeatProposalValidations:    make(map[[16]byte]bool),
+		depositRequests:                 make(map[[32]byte]*DepositChainRequest),
 		blockCounter:                    blockCounter,
 		operatorPrivateKey:              operatorPrivateKey,
 	}

pkg/tbtc/deposit.go

@@ -3,17 +3,25 @@ package tbtc
 import (
 	"encoding/hex"
 	"fmt"
+	"strings"
+
 	"github.com/keep-network/keep-core/pkg/bitcoin"
 	"github.com/keep-network/keep-core/pkg/chain"
-	"strings"
 )
 
 // depositScriptFormat is the format of the deposit P2(W)SH Bitcoin script
 // The specific placeholders are: depositor, blindingFactor, walletPublicKeyHash,
 // refundPublicKeyHash and refundLocktime. For reference see:
-// https://github.com/keep-network/tbtc-v2/blob/83310bdc9ed934e286bc9ea5091cc16979950134/solidity/contracts/bridge/Deposit.sol#L172
+// https://github.com/keep-network/tbtc-v2/blob/4b6143974b43297e69a45191f0e2b6a25561e72b/solidity/contracts/bridge/Deposit.sol#L217
 const depositScriptFormat = "14%v7508%v7576a914%v8763ac6776a914%v8804%vb175ac68"
 
+// depositWithExtraDataScriptFormat is the format of the deposit P2(W)SH Bitcoin
+// script with optional 32-byte extra data included. The specific placeholders
+// are: depositor, extraData, blindingFactor, walletPublicKeyHash, refundPublicKeyHash,
+// and refundLocktime. For reference see:
+// https://github.com/keep-network/tbtc-v2/blob/4b6143974b43297e69a45191f0e2b6a25561e72b/solidity/contracts/bridge/Deposit.sol#L246
+const depositWithExtraDataScriptFormat = "14%v7520%v7508%v7576a914%v8763ac6776a914%v8804%vb175ac68"
+
 // Deposit represents a tBTC deposit.
 type Deposit struct {
 	// Utxo is the unspent output of the deposit funding transaction that
@@ -33,6 +41,9 @@ type Deposit struct {
 	// Vault is an optional field that holds the host chain address of the
 	// target vault.
 	Vault *chain.Address
+	// ExtraData is an optional field that holds 32 bytes of extra data
+	// embedded in the deposit script.
+	ExtraData *[32]byte
 }
 
 // Script constructs the deposit P2(W)SH Bitcoin script. This function
@@ -48,14 +59,28 @@ func (d *Deposit) Script() ([]byte, error) {
 		return nil, fmt.Errorf("wrong byte length of depositor field")
 	}
 
-	script := fmt.Sprintf(
-		depositScriptFormat,
-		hex.EncodeToString(depositorBytes),
-		hex.EncodeToString(d.BlindingFactor[:]),
-		hex.EncodeToString(d.WalletPublicKeyHash[:]),
-		hex.EncodeToString(d.RefundPublicKeyHash[:]),
-		hex.EncodeToString(d.RefundLocktime[:]),
-	)
+	var script string
+
+	if d.ExtraData != nil {
+		script = fmt.Sprintf(
+			depositWithExtraDataScriptFormat,
+			hex.EncodeToString(depositorBytes),
+			hex.EncodeToString(d.ExtraData[:]),
+			hex.EncodeToString(d.BlindingFactor[:]),
+			hex.EncodeToString(d.WalletPublicKeyHash[:]),
+			hex.EncodeToString(d.RefundPublicKeyHash[:]),
+			hex.EncodeToString(d.RefundLocktime[:]),
+		)
+	} else {
+		script = fmt.Sprintf(
+			depositScriptFormat,
+			hex.EncodeToString(depositorBytes),
+			hex.EncodeToString(d.BlindingFactor[:]),
+			hex.EncodeToString(d.WalletPublicKeyHash[:]),
+			hex.EncodeToString(d.RefundPublicKeyHash[:]),
+			hex.EncodeToString(d.RefundLocktime[:]),
+		)
+	}
 
 	return hex.DecodeString(script)
 }

pkg/tbtc/deposit_sweep.go

@@ -247,6 +247,20 @@ func ValidateDepositSweepProposal(
 				FundingTx *bitcoin.Transaction
 			},
 		) error
+
+		// GetDepositRequest gets the on-chain deposit request for the given
+		// funding transaction hash and output index.The returned values represent:
+		// - deposit request which is non-nil only when the deposit request was
+		//   found,
+		// - boolean value which is true if the deposit request was found, false
+		//   otherwise,
+		// - error which is non-nil only when the function execution failed. It will
+		//   be nil if the deposit request was not found, but the function execution
+		//   succeeded.
+		GetDepositRequest(
+			fundingTxHash bitcoin.Hash,
+			fundingOutputIndex uint32,
+		) (*DepositChainRequest, bool, error)
 	},
 	btcChain bitcoin.Chain,
 ) ([]*Deposit, error) {
@@ -352,11 +366,29 @@ func ValidateDepositSweepProposal(
 			)
 		}
 
+		depositRequest, found, err := chain.GetDepositRequest(
+			depositKey.FundingTxHash,
+			depositKey.FundingOutputIndex,
+		)
+		if err != nil {
+			return nil, fmt.Errorf(
+				"cannot get request data for deposit [%v]: [%v]",
+				depositDisplayIndex,
+				err,
+			)
+		}
+		if !found {
+			return nil, fmt.Errorf(
+				"request data not found for deposit [%v]",
+				depositDisplayIndex,
+			)
+		}
+
 		depositExtraInfo[i] = struct {
 			*Deposit
 			FundingTx *bitcoin.Transaction
 		}{
-			Deposit:   matchingEvent.unpack(),
+			Deposit:   matchingEvent.unpack(depositRequest.ExtraData),
 			FundingTx: fundingTx,
 		}
 	}

pkg/tbtc/deposit_sweep_test.go

@@ -119,6 +119,18 @@ func TestDepositSweepAction_Execute(t *testing.T) {
 				if err != nil {
 					t.Fatal(err)
 				}
+
+				hostChain.setDepositRequest(
+					fundingTxHash,
+					fundingOutputIndex,
+					&DepositChainRequest{
+						// Set only relevant fields.
+						Depositor: deposit.Depositor,
+						Amount:    uint64(deposit.Utxo.Value),
+						Vault:     deposit.Vault,
+						ExtraData: deposit.ExtraData,
+					},
+				)
 			}
 
 			// Build the sweep proposal based on the scenario data.
@@ -252,6 +264,7 @@ func TestAssembleDepositSweepTransaction(t *testing.T) {
 					RefundPublicKeyHash: d.RefundPublicKeyHash,
 					RefundLocktime:      d.RefundLocktime,
 					Vault:               d.Vault,
+					ExtraData:           d.ExtraData,
 				}
 			}
 

pkg/tbtc/deposit_test.go

@@ -4,6 +4,8 @@ import (
 	"encoding/hex"
 	"testing"
 
+	"github.com/keep-network/keep-core/pkg/chain"
+
 	"github.com/keep-network/keep-core/internal/testutils"
 )
 
@@ -16,24 +18,67 @@ func TestDeposit_Script(t *testing.T) {
 		return bytes
 	}
 
-	// Fill only the fields relevant for script computation.
-	d := new(Deposit)
-	d.Depositor = "934b98637ca318a4d6e7ca6ffd1690b8e77df637"
-	copy(d.BlindingFactor[:], hexToSlice("f9f0c90d00039523"))
-	copy(d.WalletPublicKeyHash[:], hexToSlice("8db50eb52063ea9d98b3eac91489a90f738986f6"))
-	copy(d.RefundPublicKeyHash[:], hexToSlice("28e081f285138ccbe389c1eb8985716230129f89"))
-	copy(d.RefundLocktime[:], hexToSlice("60bcea61"))
-
-	script, err := d.Script()
-	if err != nil {
-		t.Fatal(err)
+	var tests = map[string]struct {
+		depositor           string
+		blindingFactor      string
+		walletPublicKeyHash string
+		refundPublicKeyHash string
+		refundLocktime      string
+		extraData           string
+		expectedScript      string
+	}{
+		"no extra data": {
+			depositor:           "934b98637ca318a4d6e7ca6ffd1690b8e77df637",
+			blindingFactor:      "f9f0c90d00039523",
+			walletPublicKeyHash: "8db50eb52063ea9d98b3eac91489a90f738986f6",
+			refundPublicKeyHash: "28e081f285138ccbe389c1eb8985716230129f89",
+			refundLocktime:      "60bcea61",
+			extraData:           "",
+			expectedScript: "14934b98637ca318a4d6e7ca6ffd1690b8e77df637750" +
+				"8f9f0c90d000395237576a9148db50eb52063ea9d98b3eac91489a90f" +
+				"738986f68763ac6776a91428e081f285138ccbe389c1eb89857162301" +
+				"29f89880460bcea61b175ac68",
+		},
+		"with extra data": {
+			depositor:           "934b98637ca318a4d6e7ca6ffd1690b8e77df637",
+			blindingFactor:      "f9f0c90d00039523",
+			walletPublicKeyHash: "8db50eb52063ea9d98b3eac91489a90f738986f6",
+			refundPublicKeyHash: "28e081f285138ccbe389c1eb8985716230129f89",
+			refundLocktime:      "60bcea61",
+			extraData: "a9b38ea6435c8941d6eda6a46b68e3e2117196995bd154ab55" +
+				"196396b03d9bda",
+			expectedScript: "14934b98637ca318a4d6e7ca6ffd1690b8e77df637752" +
+				"0a9b38ea6435c8941d6eda6a46b68e3e2117196995bd154ab55196396" +
+				"b03d9bda7508f9f0c90d000395237576a9148db50eb52063ea9d98b3e" +
+				"ac91489a90f738986f68763ac6776a91428e081f285138ccbe389c1eb" +
+				"8985716230129f89880460bcea61b175ac68",
+		},
 	}
 
-	expectedScript := hexToSlice(
-		"14934b98637ca318a4d6e7ca6ffd1690b8e77df6377508f9f0c90d0003" +
-			"95237576a9148db50eb52063ea9d98b3eac91489a90f738986f68763ac6776a" +
-			"91428e081f285138ccbe389c1eb8985716230129f89880460bcea61b175ac68",
-	)
+	for testName, test := range tests {
+		t.Run(testName, func(t *testing.T) {
+			// Fill only the fields relevant for script computation.
+			d := new(Deposit)
+			d.Depositor = chain.Address(test.depositor)
+			copy(d.BlindingFactor[:], hexToSlice(test.blindingFactor))
+			copy(d.WalletPublicKeyHash[:], hexToSlice(test.walletPublicKeyHash))
+			copy(d.RefundPublicKeyHash[:], hexToSlice(test.refundPublicKeyHash))
+			copy(d.RefundLocktime[:], hexToSlice(test.refundLocktime))
+
+			if len(test.extraData) > 0 {
+				var extraData [32]byte
+				copy(extraData[:], hexToSlice(test.extraData))
+				d.ExtraData = &extraData
+			}
+
+			script, err := d.Script()
+			if err != nil {
+				t.Fatal(err)
+			}
 
-	testutils.AssertBytesEqual(t, expectedScript, script)
+			expectedScript := hexToSlice(test.expectedScript)
+
+			testutils.AssertBytesEqual(t, expectedScript, script)
+		})
+	}
 }

pkg/tbtc/internal/test/marshaling.go

@@ -29,6 +29,7 @@ func (dsts *DepositSweepTestScenario) UnmarshalJSON(data []byte) error {
 			RefundPublicKeyHash string
 			RefundLocktime      string
 			Vault               string
+			ExtraData           string
 		}
 		InputTransactions                   []string
 		Fee                                 int64
@@ -87,6 +88,12 @@ func (dsts *DepositSweepTestScenario) UnmarshalJSON(data []byte) error {
 		}
 		d.Vault = vault
 
+		if len(deposit.ExtraData) > 0 {
+			var extraData [32]byte
+			copy(extraData[:], hexToSlice(deposit.ExtraData))
+			d.ExtraData = &extraData
+		}
+
 		dsts.Deposits = append(dsts.Deposits, d)
 	}