core: implement EIP-8254: Cap deposit requests per block

cmd/evm/internal/t8ntool/execution.go

@@ -339,7 +339,7 @@ func (pre *Prestate) Apply(vmConfig vm.Config, chainConfig *params.ChainConfig,
 		for _, receipt := range receipts {
 			allLogs = append(allLogs, receipt.Logs...)
 		}
-		if err := core.ParseDepositLogs(&requests, allLogs, chainConfig); err != nil {
+		if err := core.ParseDepositLogs(&requests, allLogs, chainConfig, vmContext.BlockNumber, vmContext.Time); err != nil {
 			return nil, nil, nil, NewError(ErrorEVM, fmt.Errorf("could not parse requests logs: %v", err))
 		}
 		// EIP-7002

core/chain_makers.go

@@ -322,7 +322,7 @@ func (b *BlockGen) collectRequests(readonly bool) (requests [][]byte) {
 		for _, r := range b.receipts {
 			blockLogs = append(blockLogs, r.Logs...)
 		}
-		if err := ParseDepositLogs(&requests, blockLogs, b.cm.config); err != nil {
+		if err := ParseDepositLogs(&requests, blockLogs, b.cm.config, b.header.Number, b.header.Time); err != nil {
 			panic(fmt.Sprintf("failed to parse deposit log: %v", err))
 		}
 		// create EVM for system calls

core/state_processor.go

@@ -143,7 +143,7 @@ func postExecution(ctx context.Context, config *params.ChainConfig, block *types
 	if config.IsPrague(block.Number(), block.Time()) {
 		requests = [][]byte{}
 		// EIP-6110
-		if err := ParseDepositLogs(&requests, allLogs, config); err != nil {
+		if err := ParseDepositLogs(&requests, allLogs, config, block.Number(), block.Time()); err != nil {
 			return requests, fmt.Errorf("failed to parse deposit logs: %w", err)
 		}
 		// EIP-7002
@@ -347,21 +347,47 @@ func processRequestsSystemCall(requests *[][]byte, evm *vm.EVM, requestType byte
 	return nil
 }
 
-var depositTopic = common.HexToHash("0x649bbc62d0e31342afea4e5cd82d4049e7e1ee912fc0889aa790803be39038c5")
+// DepositTopic is the topic hash of the EIP-6110 DepositEvent.
+var DepositTopic = common.HexToHash("0x649bbc62d0e31342afea4e5cd82d4049e7e1ee912fc0889aa790803be39038c5")
+
+// IsDepositLog reports whether the log is an EIP-6110 deposit event emitted
+// by the given deposit contract address.
+func IsDepositLog(log *types.Log, depositContract common.Address) bool {
+	return log.Address == depositContract && len(log.Topics) > 0 && log.Topics[0] == DepositTopic
+}
+
+// CountDepositLogs returns the number of EIP-6110 deposit events present in
+// the given logs.
+func CountDepositLogs(logs []*types.Log, depositContract common.Address) int {
+	count := 0
+	for _, log := range logs {
+		if IsDepositLog(log, depositContract) {
+			count++
+		}
+	}
+	return count
+}
 
 // ParseDepositLogs extracts the EIP-6110 deposit values from logs emitted by
-// BeaconDepositContract.
+// BeaconDepositContract. From the Amsterdam fork onwards the number of
-func ParseDepositLogs(requests *[][]byte, logs []*types.Log, config *params.ChainConfig) error {
+// deposits per block is capped to params.MaxDepositRequestsPerBlock by
+// EIP-8254.
+func ParseDepositLogs(requests *[][]byte, logs []*types.Log, config *params.ChainConfig, blockNumber *big.Int, blockTime uint64) error {
 	deposits := make([]byte, 1) // note: first byte is 0x00 (== deposit request type)
+	count := 0
 	for _, log := range logs {
-		if log.Address == config.DepositContractAddress && len(log.Topics) > 0 && log.Topics[0] == depositTopic {
+		if IsDepositLog(log, config.DepositContractAddress) {
 			request, err := types.DepositLogToRequest(log.Data)
 			if err != nil {
 				return fmt.Errorf("unable to parse deposit data: %v", err)
 			}
 			deposits = append(deposits, request...)
+			count++
 		}
 	}
+	if config.IsAmsterdam(blockNumber, blockTime) && count > params.MaxDepositRequestsPerBlock {
+		return fmt.Errorf("too many deposit requests in block: have %d, max %d", count, params.MaxDepositRequestsPerBlock)
+	}
 	if len(deposits) > 1 {
 		*requests = append(*requests, deposits)
 	}

internal/ethapi/simulate.go

@@ -398,7 +398,7 @@ func (sim *simulator) processBlock(ctx context.Context, block *simBlock, header,
 	if sim.chainConfig.IsPrague(header.Number, header.Time) {
 		requests = [][]byte{}
 		// EIP-6110
-		if err := core.ParseDepositLogs(&requests, allLogs, sim.chainConfig); err != nil {
+		if err := core.ParseDepositLogs(&requests, allLogs, sim.chainConfig, header.Number, header.Time); err != nil {
 			return nil, nil, nil, err
 		}
 		// EIP-7002

miner/worker.go

@@ -43,6 +43,10 @@ var (
 	errBlockInterruptedByNewHead  = errors.New("new head arrived while building block")
 	errBlockInterruptedByRecommit = errors.New("recommit interrupt while building block")
 	errBlockInterruptedByTimeout  = errors.New("timeout while building block")
+
+	// errDepositCapExceeded is returned when including a transaction would
+	// push the block over the EIP-8254 deposit-request cap.
+	errDepositCapExceeded = errors.New("deposit request cap exceeded")
 )
 
 // maxBlobsPerBlock returns the maximum number of blobs per block.
@@ -66,11 +70,12 @@ type environment struct {
 	coinbase common.Address
 	evm      *vm.EVM
 
-	header   *types.Header
+	header          *types.Header
-	txs      []*types.Transaction
+	txs             []*types.Transaction
-	receipts []*types.Receipt
+	receipts        []*types.Receipt
-	sidecars []*types.BlobTxSidecar
+	sidecars        []*types.BlobTxSidecar
-	blobs    int
+	blobs           int
+	depositRequests int // running count of EIP-6110 deposit requests, capped by EIP-8254
 
 	witness *stateless.Witness
 }
@@ -212,7 +217,7 @@ func (miner *Miner) generateWork(ctx context.Context, genParam *generateParams,
 	if miner.chainConfig.IsPrague(work.header.Number, work.header.Time) {
 		requests = [][]byte{}
 		// EIP-6110 deposits
-		if err := core.ParseDepositLogs(&requests, allLogs, miner.chainConfig); err != nil {
+		if err := core.ParseDepositLogs(&requests, allLogs, miner.chainConfig, work.header.Number, work.header.Time); err != nil {
 			return &newPayloadResult{err: err}
 		}
 		// EIP-7002
@@ -372,10 +377,13 @@ func (miner *Miner) commitTransaction(ctx context.Context, env *environment, tx
 	if tx.Type() == types.BlobTxType {
 		return miner.commitBlobTransaction(env, tx)
 	}
-	receipt, err := miner.applyTransaction(env, tx)
+	receipt, snap, gp, err := miner.applyTransaction(env, tx)
 	if err != nil {
 		return err
 	}
+	if err := miner.checkDepositCap(env, receipt, snap, gp); err != nil {
+		return err
+	}
 	env.txs = append(env.txs, tx)
 	env.receipts = append(env.receipts, receipt)
 	env.size += tx.Size()
@@ -396,10 +404,13 @@ func (miner *Miner) commitBlobTransaction(env *environment, tx *types.Transactio
 	if env.blobs+len(sc.Blobs) > maxBlobs {
 		return errors.New("max data blobs reached")
 	}
-	receipt, err := miner.applyTransaction(env, tx)
+	receipt, snap, gp, err := miner.applyTransaction(env, tx)
 	if err != nil {
 		return err
 	}
+	if err := miner.checkDepositCap(env, receipt, snap, gp); err != nil {
+		return err
+	}
 	txNoBlob := tx.WithoutBlobTxSidecar()
 	env.txs = append(env.txs, txNoBlob)
 	env.receipts = append(env.receipts, receipt)
@@ -412,7 +423,9 @@ func (miner *Miner) commitBlobTransaction(env *environment, tx *types.Transactio
 }
 
 // applyTransaction runs the transaction. If execution fails, state and gas pool are reverted.
-func (miner *Miner) applyTransaction(env *environment, tx *types.Transaction) (*types.Receipt, error) {
+// On success the pre-execution snapshot/gas-pool checkpoint are returned so the
+// caller can revert if a post-execution constraint (e.g. EIP-8254 deposit cap) fails.
+func (miner *Miner) applyTransaction(env *environment, tx *types.Transaction) (*types.Receipt, int, *core.GasPool, error) {
 	var (
 		snap = env.state.Snapshot()
 		gp   = env.gasPool.Snapshot()
@@ -421,10 +434,32 @@ func (miner *Miner) applyTransaction(env *environment, tx *types.Transaction) (*
 	if err != nil {
 		env.state.RevertToSnapshot(snap)
 		env.gasPool.Set(gp)
-		return nil, err
+		return nil, 0, nil, err
 	}
 	env.header.GasUsed = env.gasPool.Used()
-	return receipt, nil
+	return receipt, snap, gp, nil
+}
+
+// checkDepositCap enforces the EIP-8254 cap on deposit requests per block.
+// If including the receipt would push the running deposit count over
+// params.MaxDepositRequestsPerBlock, the state and gas pool are reverted to
+// the pre-execution checkpoint and errDepositCapExceeded is returned.
+func (miner *Miner) checkDepositCap(env *environment, receipt *types.Receipt, snap int, gp *core.GasPool) error {
+	if !miner.chainConfig.IsAmsterdam(env.header.Number, env.header.Time) {
+		return nil
+	}
+	added := core.CountDepositLogs(receipt.Logs, miner.chainConfig.DepositContractAddress)
+	if added == 0 {
+		return nil
+	}
+	if env.depositRequests+added > params.MaxDepositRequestsPerBlock {
+		env.state.RevertToSnapshot(snap)
+		env.gasPool.Set(gp)
+		env.header.GasUsed = env.gasPool.Used()
+		return errDepositCapExceeded
+	}
+	env.depositRequests += added
+	return nil
 }
 
 func (miner *Miner) commitTransactions(ctx context.Context, env *environment, plainTxs, blobTxs *transactionsByPriceAndNonce, interrupt *atomic.Int32) error {
@@ -522,6 +557,13 @@ func (miner *Miner) commitTransactions(ctx context.Context, env *environment, pl
 
 		err := miner.commitTransaction(ctx, env, tx)
 		switch {
+		case errors.Is(err, errDepositCapExceeded):
+			// EIP-8254: including this tx would push the block past the
+			// deposit-request cap. Skip this sender; subsequent senders may
+			// still produce non-deposit-bearing transactions that fit.
+			log.Trace("Skipping tx that would exceed deposit-request cap", "hash", ltx.Hash, "sender", from)
+			txs.Pop()
+
 		case errors.Is(err, core.ErrNonceTooLow):
 			// New head notification data race between the transaction pool and miner, shift
 			log.Trace("Skipping transaction with low nonce", "hash", ltx.Hash, "sender", from, "nonce", tx.Nonce())

params/protocol_params.go

@@ -186,6 +186,8 @@ const (
 	HistoryServeWindow = 8191 // Number of blocks to serve historical block hashes for, EIP-2935.
 
 	MaxBlockSize = 8_388_608 // maximum size of an RLP-encoded block
+
+	MaxDepositRequestsPerBlock = 8192 // Maximum number of EIP-6110 deposit requests per block, EIP-8254.
 )
 
 // Bls12381G1MultiExpDiscountTable is the gas discount table for BLS12-381 G1 multi exponentiation operation