Merge pull request #1112 from rocket-pool/bundle-distribution

Add Flashbots bundle support for minipool close

Author: 0xfornax

bindings/minipool/minipool-contract-v3.go

@@ -33,6 +33,7 @@ type MinipoolV3 interface {
 	GetUserDistributed(opts *bind.CallOpts) (bool, error)
 	EstimateDistributeBalanceGas(rewardsOnly bool, opts *bind.TransactOpts) (rocketpool.GasInfo, error)
 	DistributeBalance(rewardsOnly bool, opts *bind.TransactOpts) (common.Hash, error)
+	PrepareDistributeBalance(rewardsOnly bool, opts *bind.TransactOpts) (*types.Transaction, error)
 }
 
 // Minipool contract
@@ -388,6 +389,20 @@ func (mp *minipool_v3) DistributeBalance(rewardsOnly bool, opts *bind.TransactOp
 	return tx.Hash(), nil
 }
 
+// PrepareDistributeBalance is like DistributeBalance but forces NoSend and returns the signed transaction
+// (instead of sending it). Useful for assembling Flashbots bundles.
+func (mp *minipool_v3) PrepareDistributeBalance(rewardsOnly bool, opts *bind.TransactOpts) (*types.Transaction, error) {
+	if opts == nil {
+		opts = &bind.TransactOpts{}
+	}
+	opts.NoSend = true
+	tx, err := mp.Contract.Transact(opts, "distributeBalance", rewardsOnly)
+	if err != nil {
+		return nil, fmt.Errorf("error preparing distribute tx for minipool %s: %w", mp.Address.Hex(), err)
+	}
+	return tx, nil
+}
+
 // Estimate the gas of Stake
 func (mp *minipool_v3) EstimateStakeGas(validatorSignature rptypes.ValidatorSignature, depositDataRoot common.Hash, opts *bind.TransactOpts) (rocketpool.GasInfo, error) {
 	return mp.Contract.GetTransactionGasInfo(opts, "stake", validatorSignature[:], depositDataRoot)

bindings/node/distributor.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
 
 	"github.com/rocket-pool/smartnode/bindings/rocketpool"
 )
@@ -62,6 +63,20 @@ func (d *Distributor) Distribute(opts *bind.TransactOpts) (common.Hash, error) {
 	return tx.Hash(), nil
 }
 
+// PrepareDistribute is like Distribute but forces NoSend and returns the signed transaction
+// (instead of sending it). Useful for assembling Flashbots bundles.
+func (d *Distributor) PrepareDistribute(opts *bind.TransactOpts) (*types.Transaction, error) {
+	if opts == nil {
+		opts = &bind.TransactOpts{}
+	}
+	opts.NoSend = true
+	tx, err := d.Contract.Transact(opts, "distribute")
+	if err != nil {
+		return nil, fmt.Errorf("error preparing distribute tx for distributor %s: %w", d.Address.Hex(), err)
+	}
+	return tx, nil
+}
+
 // Gets the node share of the distributor's current balance
 func (d *Distributor) GetNodeShare(opts *bind.CallOpts) (*big.Int, error) {
 	nodeShare := new(*big.Int)

rocketpool-cli/minipool/close.go

@@ -21,7 +21,7 @@ import (
 	"github.com/rocket-pool/smartnode/shared/utils/math"
 )
 
-func closeMinipools(minipool string, confirmSlashing, yes bool) error {
+func closeMinipools(minipool string, confirmSlashing, yes, bundle bool) error {
 
 	// Get RP client
 	rp, err := rocketpool.NewClient().WithReady()
@@ -272,7 +272,7 @@ func closeMinipools(minipool string, confirmSlashing, yes bool) error {
 	// Close minipools
 	for _, minipool := range selectedMinipools {
 
-		response, err := rp.CloseMinipool(minipool.Address)
+		response, err := rp.CloseMinipool(minipool.Address, bundle)
 		if err != nil {
 			fmt.Printf("Could not close minipool %s: %s.\n", minipool.Address.Hex(), err.Error())
 			continue

rocketpool-cli/minipool/commands.go

@@ -265,6 +265,11 @@ func RegisterCommands(app *cli.Command, name string, aliases []string) {
 						Name:  "confirm-slashing",
 						Usage: "Reserved for acknowledging situations where you've been slashed by the Beacon Chain, and closing a minipool will result in the complete loss of the ETH bond and your RPL collateral. DO NOT use this flag unless you have been explicitly instructed to do so.",
 					},
+					&cli.BoolFlag{
+						Name:    "bundle",
+						Aliases: []string{"b"},
+						Usage:   "Force closing via a Flashbots bundle (distribute + finalise). Without this flag, a bundle is still used automatically if your fee distributor has a balance. Mainnet only.",
+					},
 				},
 				Action: func(ctx context.Context, c *cli.Command) error {
 
@@ -281,7 +286,7 @@ func RegisterCommands(app *cli.Command, name string, aliases []string) {
 					}
 
 					// Run
-					return closeMinipools(c.String("minipool"), c.Bool("confirm-slashing"), c.Bool("yes"))
+					return closeMinipools(c.String("minipool"), c.Bool("confirm-slashing"), c.Bool("yes"), c.Bool("bundle"))
 
 				},
 			},

rocketpool/api/minipool/close.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
+	gethtypes "github.com/ethereum/go-ethereum/core/types"
 	"github.com/urfave/cli/v3"
 	"golang.org/x/sync/errgroup"
 
@@ -18,9 +19,13 @@ import (
 
 	"github.com/rocket-pool/smartnode/shared/services"
 	"github.com/rocket-pool/smartnode/shared/services/beacon"
+	"github.com/rocket-pool/smartnode/shared/services/flashbots"
 	"github.com/rocket-pool/smartnode/shared/types/api"
 )
 
+// Gas can't be estimated against current chain state (the fee distributor's distribute() in the bundle hasn't executed yet)
+const distributeBalanceBundleGasLimit uint64 = 600000
+
 func getMinipoolCloseDetailsForNode(c *cli.Command) (*api.GetMinipoolCloseDetailsForNodeResponse, error) {
 
 	// Get services
@@ -307,7 +312,7 @@ func getMinipoolCloseDetails(rp *rocketpool.RocketPool, minipoolAddress common.A
 
 }
 
-func closeMinipool(c *cli.Command, minipoolAddress common.Address, opts *bind.TransactOpts) (*api.CloseMinipoolResponse, error) {
+func closeMinipool(c *cli.Command, minipoolAddress common.Address, opts *bind.TransactOpts, bundle bool) (*api.CloseMinipoolResponse, error) {
 
 	// Get services
 	if err := services.RequireNodeRegistered(c); err != nil {
@@ -373,12 +378,91 @@ func closeMinipool(c *cli.Command, minipoolAddress common.Address, opts *bind.Tr
 		}
 		response.TxHash = hash
 	} else {
-		// Do a distribution, which will finalize it
-		hash, err := mpv3.DistributeBalance(false, opts)
+		cfg, err := services.GetConfig(c)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("error getting config: %w", err)
 		}
-		response.TxHash = hash
+
+		ec, err := services.GetEthClient(c)
+		if err != nil {
+			return nil, fmt.Errorf("error getting eth client: %w", err)
+		}
+
+		relayUrl := cfg.Smartnode.GetFlashbotsRelayUrl()
+		useBundle := bundle
+		if useBundle && relayUrl == "" {
+			return nil, fmt.Errorf("a bundle was requested but Flashbots bundles are only supported on mainnet; there is no relay for this network")
+		}
+
+		var distributorAddress common.Address
+		if relayUrl != "" {
+			w, err := services.GetWallet(c)
+			if err != nil {
+				return nil, err
+			}
+			nodeAccount, err := w.GetNodeAccount()
+			if err != nil {
+				return nil, err
+			}
+			distributorAddress, err = node.GetDistributorAddress(rp, nodeAccount.Address, nil)
+			if err != nil {
+				return nil, fmt.Errorf("error getting fee distributor address: %w", err)
+			}
+
+			if !useBundle {
+				distributorBalance, err := ec.BalanceAt(context.Background(), distributorAddress, nil)
+				if err != nil {
+					return nil, fmt.Errorf("error getting fee distributor balance: %w", err)
+				}
+				useBundle = distributorBalance.Cmp(big.NewInt(1)) == 0
+			}
+		}
+
+		if !useBundle {
+			// Do a plain distribution, which will finalize it
+			hash, err := mpv3.DistributeBalance(false, opts)
+			if err != nil {
+				return nil, err
+			}
+			response.TxHash = hash
+			return &response, nil
+		}
+
+		// Empty the fee distributor and distribute the minipool balance (which also finalizes
+		// it) atomically in the same block via a Flashbots bundle.
+		distributor, err := node.NewDistributor(rp, distributorAddress, nil)
+		if err != nil {
+			return nil, fmt.Errorf("error creating fee distributor binding: %w", err)
+		}
+
+		// First tx: fee distributor distribute()
+		distributorTx, err := distributor.PrepareDistribute(opts)
+		if err != nil {
+			return nil, fmt.Errorf("error preparing fee distributor distribute tx for bundle: %w", err)
+		}
+
+		// Second tx: minipool distributeBalance(), with bumped nonce and a fixed gas limit
+		opts.Nonce = new(big.Int).SetUint64(distributorTx.Nonce() + 1)
+		opts.GasLimit = distributeBalanceBundleGasLimit
+
+		distBalTx, err := mpv3.PrepareDistributeBalance(false, opts)
+		if err != nil {
+			return nil, fmt.Errorf("error preparing distribute balance tx for bundle on minipool %s: %w", minipoolAddress.Hex(), err)
+		}
+
+		// Send the 2-tx bundle (distribute then distributeBalance)
+		timeoutCtx, cancel := context.WithTimeout(context.Background(), flashbots.DefaultSubmissionTimeout)
+		success, err := flashbots.SubmitBundleAndWait(timeoutCtx, nil, ec, relayUrl, []*gethtypes.Transaction{distributorTx, distBalTx}, flashbots.DefaultBundleBlockCount)
+		cancel()
+		if err != nil {
+			return nil, fmt.Errorf("error sending bundle for distribute+distributeBalance: %w", err)
+		}
+		if !success {
+			return nil, fmt.Errorf("bundle for minipool %s distribute+distributeBalance was not included. Bundles usually require a higher priority fee to get included", minipoolAddress.Hex())
+		}
+
+		// Report the distributeBalance tx hash (the last tx in the bundle).
+		response.TxHash = distBalTx.Hash()
 	}
 
 	// Return response

rocketpool/api/minipool/routes.go

@@ -155,7 +155,8 @@ func RegisterRoutes(mux *http.ServeMux, c *cli.Command) {
 			apiutils.WriteErrorResponse(w, err)
 			return
 		}
-		resp, err := closeMinipool(c, addr, opts)
+		bundle := r.FormValue("bundle") == "true"
+		resp, err := closeMinipool(c, addr, opts, bundle)
 		apiutils.WriteResponse(w, resp, err)
 	})
 

shared/services/config/smartnode-config.go

@@ -220,6 +220,9 @@ type SmartnodeConfig struct {
 
 	// The FlashBots Protect RPC endpoint
 	flashbotsProtectUrl map[config.Network]string `yaml:"-"`
+
+	// The Flashbots relay URL for eth_sendBundle / bundle operations (distinct from Protect RPC)
+	flashbotsRelayUrl map[config.Network]string `yaml:"-"`
 }
 
 // Generates a newSmart Node configuration
@@ -635,6 +638,10 @@ func NewSmartnodeConfig(cfg *RocketPoolConfig) *SmartnodeConfig {
 			config.Network_Devnet:  "https://rpc-hoodi.flashbots.net/",
 			config.Network_Testnet: "https://rpc-hoodi.flashbots.net/",
 		},
+
+		flashbotsRelayUrl: map[config.Network]string{
+			config.Network_Mainnet: "https://relay.flashbots.net",
+		},
 	}
 
 }
@@ -993,6 +1000,10 @@ func (cfg *SmartnodeConfig) GetFlashbotsProtectUrl() string {
 	return cfg.flashbotsProtectUrl[cfg.Network.Value.(config.Network)]
 }
 
+func (cfg *SmartnodeConfig) GetFlashbotsRelayUrl() string {
+	return cfg.flashbotsRelayUrl[cfg.Network.Value.(config.Network)]
+}
+
 func getNetworkOptions() []config.ParameterOption {
 	options := []config.ParameterOption{
 		{