core, params, beacon/engine: implement EIP 4788 BeaconRoot

beacon/engine/types.go

@@ -226,6 +226,7 @@ func ExecutableDataToBlock(params ExecutableData, versionedHashes []common.Hash)
 		WithdrawalsHash: withdrawalsRoot,
 		ExcessBlobGas:   params.ExcessBlobGas,
 		BlobGasUsed:     params.BlobGasUsed,
+		// TODO BeaconRoot
 	}
 	block := types.NewBlockWithHeader(header).WithBody(txs, nil /* uncles */).WithWithdrawals(params.Withdrawals)
 	if block.Hash() != params.BlockHash {
@@ -255,6 +256,7 @@ func BlockToExecutableData(block *types.Block, fees *big.Int, blobs []kzg4844.Bl
 		Withdrawals:   block.Withdrawals(),
 		BlobGasUsed:   block.BlobGasUsed(),
 		ExcessBlobGas: block.ExcessBlobGas(),
+		// TODO BeaconRoot
 	}
 	blobsBundle := BlobsBundleV1{
 		Commitments: make([]hexutil.Bytes, 0),

consensus/beacon/consensus.go

@@ -269,15 +269,21 @@ func (beacon *Beacon) verifyHeader(chain consensus.ChainHeaderReader, header, pa
 	if !shanghai && header.WithdrawalsHash != nil {
 		return fmt.Errorf("invalid withdrawalsHash: have %x, expected nil", header.WithdrawalsHash)
 	}
-	// Verify the existence / non-existence of excessBlobGas
+	// Verify the existence / non-existence of cancun-specific header fields
 	cancun := chain.Config().IsCancun(header.Number, header.Time)
-	if !cancun && header.ExcessBlobGas != nil {
-		return fmt.Errorf("invalid excessBlobGas: have %d, expected nil", header.ExcessBlobGas)
-	}
-	if !cancun && header.BlobGasUsed != nil {
-		return fmt.Errorf("invalid blobGasUsed: have %d, expected nil", header.BlobGasUsed)
-	}
-	if cancun {
+	if !cancun {
+		switch {
+		case header.ExcessBlobGas != nil:
+			return fmt.Errorf("invalid excessBlobGas: have %d, expected nil", header.ExcessBlobGas)
+		case header.BlobGasUsed != nil:
+			return fmt.Errorf("invalid blobGasUsed: have %d, expected nil", header.BlobGasUsed)
+		case header.BeaconRoot != nil:
+			return fmt.Errorf("invalid beaconRoot, have %#x, expected nil", header.BeaconRoot)
+		}
+	} else {
+		if header.BeaconRoot == nil {
+			return errors.New("header is missing beaconRoot")
+		}
 		if err := eip4844.VerifyEIP4844Header(parent, header); err != nil {
 			return err
 		}

core/genesis.go

@@ -485,6 +485,9 @@ func (g *Genesis) ToBlock() *types.Block {
 			if head.BlobGasUsed == nil {
 				head.BlobGasUsed = new(uint64)
 			}
+			if head.BeaconRoot == nil {
+				head.BeaconRoot = new(common.Hash)
+			}
 		}
 	}
 	return types.NewBlock(head, nil, nil, nil, trie.NewStackTrie(nil)).WithWithdrawals(withdrawals)

core/state_processor.go

@@ -66,6 +66,7 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 		blockNumber = block.Number()
 		allLogs     []*types.Log
 		gp          = new(GasPool).AddGas(block.GasLimit())
+		beaconRoot  *common.Hash
 	)
 	// Mutate the block and state according to any hard-fork specs
 	if p.config.DAOForkSupport && p.config.DAOForkBlock != nil && p.config.DAOForkBlock.Cmp(block.Number()) == 0 {
@@ -76,6 +77,24 @@ func (p *StateProcessor) Process(block *types.Block, statedb *state.StateDB, cfg
 		vmenv   = vm.NewEVM(context, vm.TxContext{}, statedb, p.config, cfg)
 		signer  = types.MakeSigner(p.config, header.Number, header.Time)
 	)
+	if beaconRoot != nil {
+		// If EIP-4788 is enabled, we need to invoke the beaconroot storage contract with
+		// the new root
+		// TODO: Right now, I set the GasXX fields to 0. If this does not work,
+		// we can use the header.BaseFee and set that instead.
+		msg := &Message{
+			From:      params.SystemAddress,
+			GasLimit:  100_000,
+			GasPrice:  new(big.Int).SetUint64(0), // TODO use nil?
+			GasFeeCap: new(big.Int).SetUint64(0), // TODO use basefee?
+			GasTipCap: new(big.Int).SetUint64(0), // TODO use zero?
+			To:        &params.BeaconRootsStorageAddress,
+			Data:      (*beaconRoot)[:], // TODO use 4byte invocation?
+		}
+		vmenv.Reset(NewEVMTxContext(msg), statedb)
+		_, _, _ = vmenv.Call(vm.AccountRef(msg.From), *msg.To, msg.Data, 100_000, nil)
+		statedb.Finalise(true)
+	}
 	// Iterate over and process the individual transactions
 	for i, tx := range block.Transactions() {
 		msg, err := TransactionToMessage(tx, signer, header.BaseFee)

core/state_processor_test.go

@@ -410,6 +410,9 @@ func GenerateBadBlock(parent *types.Block, engine consensus.Engine, txs types.Tr
 		used := uint64(nBlobs * params.BlobTxBlobGasPerBlob)
 		header.ExcessBlobGas = &excess
 		header.BlobGasUsed = &used
+
+		beaconRoot := common.HexToHash("0xbeac00")
+		header.BeaconRoot = &beaconRoot
 	}
 	// Assemble and return the final block for sealing
 	if config.IsShanghai(header.Number, header.Time) {

core/types/block.go

@@ -90,6 +90,9 @@ type Header struct {
 
 	// ExcessBlobGas was added by EIP-4844 and is ignored in legacy headers.
 	ExcessBlobGas *uint64 `json:"excessBlobGas" rlp:"optional"`
+
+	// BeaconRoot was added by EIP-4788 and is ignored in legacy headers.
+	BeaconRoot *common.Hash `json:"parentBeaconBlockRoot" rlp:"optional"`
 }
 
 // field type overrides for gencodec
@@ -297,6 +300,10 @@ func CopyHeader(h *Header) *Header {
 		cpy.BlobGasUsed = new(uint64)
 		*cpy.BlobGasUsed = *h.BlobGasUsed
 	}
+	if h.BeaconRoot != nil {
+		cpy.BeaconRoot = new(common.Hash)
+		*cpy.BeaconRoot = *h.BeaconRoot
+	}
 	return &cpy
 }
 

params/protocol_params.go

@@ -16,7 +16,11 @@
 
 package params
 
-import "math/big"
+import (
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+)
 
 const (
 	GasLimitBoundDivisor uint64 = 1024               // The bound divisor of the gas limit, used in update calculations.
@@ -179,4 +183,7 @@ var (
 	GenesisDifficulty      = big.NewInt(131072) // Difficulty of the Genesis block.
 	MinimumDifficulty      = big.NewInt(131072) // The minimum that the difficulty may ever be.
 	DurationLimit          = big.NewInt(13)     // The decision boundary on the blocktime duration used to determine whether difficulty should go up or not.
+
+	BeaconRootsStorageAddress common.Address = common.BytesToAddress([]byte{0xb}) // Address where historical beacon roots are stored as per EIP-4788
+	SystemAddress             common.Address = common.Address{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xfe}
 )