Make excess_blobs Header field optional

In order to be backwards compatible with prior forks, the excess_blobs
field must not be set until we're on an EIP-4844 compatible fork.

This patch also fixes several bugs and now we're passing all
tests.

Author: Inphi

cmd/evm/internal/t8ntool/block.go

@@ -54,7 +54,7 @@ type header struct {
 	MixDigest   common.Hash       `json:"mixHash"`
 	Nonce       *types.BlockNonce `json:"nonce"`
 	BaseFee     *big.Int          `json:"baseFeePerGas" rlp:"optional"`
-	ExcessBlobs uint64            `json:"excessBlobs"   rlp:"optional"`
+	ExcessBlobs *uint64           `json:"excessBlobs"   rlp:"optional"`
 }
 
 type headerMarshaling struct {

cmd/evm/internal/t8ntool/gen_header.go

@@ -262,8 +262,19 @@ func (beacon *Beacon) verifyHeader(chain consensus.ChainHeaderReader, header, pa
 	if diff := new(big.Int).Sub(header.Number, parent.Number); diff.Cmp(common.Big1) != 0 {
 		return consensus.ErrInvalidNumber
 	}
-	// Verify the header's EIP-1559 attributes.
-	return misc.VerifyEip1559Header(chain.Config(), parent, header)
+	if chain.Config().IsLondon(header.Number) {
+		// Verify the header's EIP-1559 attributes.
+		if err := misc.VerifyEip1559Header(chain.Config(), parent, header); err != nil {
+			return err
+		}
+	}
+	if chain.Config().IsSharding(header.Number) {
+		// Verify the header's EIP-4844 attributes.
+		if err := misc.VerifyEip4844Header(chain.Config(), parent, header); err != nil {
+			return err
+		}
+	}
+	return nil
 }
 
 // verifyHeaders is similar to verifyHeader, but verifies a batch of headers
@@ -332,8 +343,10 @@ func (beacon *Beacon) Finalize(chain consensus.ChainHeaderReader, header *types.
 	// The block reward is no longer handled here. It's done by the
 	// external consensus engine.
 	header.Root = state.IntermediateRoot(true)
-	if parent := chain.GetHeaderByHash(header.ParentHash); parent != nil {
-		header.ExcessBlobs = misc.CalcExcessBlobTransactions(parent, uint64(misc.CountBlobs(txs)))
+	if chain.Config().IsSharding(header.Number) {
+		if parent := chain.GetHeaderByHash(header.ParentHash); parent != nil {
+			header.SetExcessBlobs(misc.CalcExcessBlobTransactions(parent, uint64(misc.CountBlobs(txs))))
+		}
 	}
 }
 

consensus/beacon/consensus.go

@@ -345,6 +345,14 @@ func (c *Clique) verifyCascadingFields(chain consensus.ChainHeaderReader, header
 		// Verify the header's EIP-1559 attributes.
 		return err
 	}
+	if !chain.Config().IsSharding(header.Number) {
+		if header.ExcessBlobs != nil {
+			return fmt.Errorf("invalid excessBlobs before fork: have %d, want <nil>", *header.ExcessBlobs)
+		}
+	} else if err := misc.VerifyEip4844Header(chain.Config(), parent, header); err != nil {
+		// Verify the header's EIP-4844 attributes.
+		return err
+	}
 	// Retrieve the snapshot needed to verify this header and cache it
 	snap, err := c.snapshot(chain, number-1, header.ParentHash, parents)
 	if err != nil {
@@ -568,8 +576,10 @@ func (c *Clique) Finalize(chain consensus.ChainHeaderReader, header *types.Heade
 	// No block rewards in PoA, so the state remains as is and uncles are dropped
 	header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number))
 	header.UncleHash = types.CalcUncleHash(nil)
-	if parent := chain.GetHeaderByHash(header.ParentHash); parent != nil {
-		header.ExcessBlobs = misc.CalcExcessBlobTransactions(parent, uint64(misc.CountBlobs(txs)))
+	if chain.Config().IsSharding(header.Number) {
+		if parent := chain.GetHeaderByHash(header.ParentHash); parent != nil {
+			header.SetExcessBlobs(misc.CalcExcessBlobTransactions(parent, uint64(misc.CountBlobs(txs))))
+		}
 	}
 }
 
@@ -746,7 +756,9 @@ func encodeSigHeader(w io.Writer, header *types.Header) {
 	if header.BaseFee != nil {
 		enc = append(enc, header.BaseFee)
 	}
-	enc = append(enc, header.ExcessBlobs)
+	if header.ExcessBlobs != nil {
+		enc = append(enc, header.ExcessBlobs)
+	}
 	if err := rlp.Encode(w, enc); err != nil {
 		panic("can't encode: " + err.Error())
 	}

consensus/clique/clique.go

@@ -306,6 +306,14 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainHeaderReader, header, pa
 		// Verify the header's EIP-1559 attributes.
 		return err
 	}
+	if !chain.Config().IsSharding(header.Number) {
+		if header.ExcessBlobs != nil {
+			return fmt.Errorf("invalid excessBlobs before fork: have %d, expected 'nil'", *header.ExcessBlobs)
+		}
+	} else if err := misc.VerifyEip4844Header(chain.Config(), parent, header); err != nil {
+		// Verify the header's EIP-4844 attributes.
+		return err
+	}
 	// Verify that the block number is parent's +1
 	if diff := new(big.Int).Sub(header.Number, parent.Number); diff.Cmp(big.NewInt(1)) != 0 {
 		return consensus.ErrInvalidNumber
@@ -601,8 +609,10 @@ func (ethash *Ethash) Finalize(chain consensus.ChainHeaderReader, header *types.
 	// Accumulate any block and uncle rewards and commit the final state root
 	accumulateRewards(chain.Config(), state, header, uncles)
 	header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number))
-	if parent := chain.GetHeaderByHash(header.ParentHash); parent != nil {
-		header.ExcessBlobs = misc.CalcExcessBlobTransactions(parent, uint64(misc.CountBlobs(txs)))
+	if chain.Config().IsSharding(header.Number) {
+		if parent := chain.GetHeaderByHash(header.ParentHash); parent != nil {
+			header.SetExcessBlobs(misc.CalcExcessBlobTransactions(parent, uint64(misc.CountBlobs(txs))))
+		}
 	}
 }
 
@@ -638,7 +648,9 @@ func (ethash *Ethash) SealHash(header *types.Header) (hash common.Hash) {
 	if header.BaseFee != nil {
 		enc = append(enc, header.BaseFee)
 	}
-	enc = append(enc, header.ExcessBlobs)
+	if header.ExcessBlobs != nil {
+		enc = append(enc, header.ExcessBlobs)
+	}
 	rlp.Encode(hasher, enc)
 	hasher.Sum(hash[:0])
 	return hash

consensus/ethash/consensus.go

@@ -17,6 +17,7 @@
 package misc
 
 import (
+	"fmt"
 	"math"
 
 	"github.com/ethereum/go-ethereum/core/types"
@@ -25,7 +26,11 @@ import (
 
 // CalcExcessBlobTransactions calculates the number of blobs above the target
 func CalcExcessBlobTransactions(parent *types.Header, blobs uint64) uint64 {
-	adjusted := parent.ExcessBlobs + blobs
+	var excessBlobs uint64
+	if parent.ExcessBlobs != nil {
+		excessBlobs = *parent.ExcessBlobs
+	}
+	adjusted := excessBlobs + blobs
 	if adjusted < params.TargetBlobsPerBlock {
 		return 0
 	}
@@ -40,10 +45,19 @@ func FakeExponential(num uint64, denom uint64) uint64 {
 		(uint64(math.Pow(float64(fractional), 2))*cofactor)/denom)/(denom*3)
 }
 
+// CountBlobs returns the number of blob transactions in txs
 func CountBlobs(txs []*types.Transaction) int {
 	var count int
 	for _, tx := range txs {
 		count += len(tx.DataHashes())
 	}
 	return count
 }
+
+// VerifyEip4844Header verifies that the header is not malformed
+func VerifyEip4844Header(config *params.ChainConfig, parent, header *types.Header) error {
+	if header.ExcessBlobs == nil {
+		return fmt.Errorf("header is missing excessBlobs")
+	}
+	return nil
+}

consensus/misc/eip4844.go

@@ -65,9 +65,11 @@ type ExecutableDataV1 struct {
 	Timestamp     uint64         `json:"timestamp"     gencodec:"required"`
 	ExtraData     []byte         `json:"extraData"     gencodec:"required"`
 	BaseFeePerGas *big.Int       `json:"baseFeePerGas" gencodec:"required"`
-	ExcessBlobs   uint64         `json:"excessBlobs"   gencodec:"required"`
 	BlockHash     common.Hash    `json:"blockHash"     gencodec:"required"`
 	Transactions  [][]byte       `json:"transactions"  gencodec:"required"`
+
+	// New in EIP-4844
+	ExcessBlobs *uint64 `json:"excessBlobs"   gencodec:"optional"`
 }
 
 // JSON type overrides for executableData.
@@ -77,7 +79,7 @@ type executableDataMarshaling struct {
 	GasUsed       hexutil.Uint64
 	Timestamp     hexutil.Uint64
 	BaseFeePerGas *hexutil.Big
-	ExcessBlobs   hexutil.Uint64
+	ExcessBlobs   *hexutil.Uint64
 	ExtraData     hexutil.Bytes
 	LogsBloom     hexutil.Bytes
 	Transactions  []hexutil.Bytes

core/beacon/gen_ed.go

@@ -3913,6 +3913,7 @@ func TestDataBlobTxs(t *testing.T) {
 
 	blocks, _ := GenerateChain(gspec.Config, genesis, engine, db, 1, func(i int, b *BlockGen) {
 		b.SetCoinbase(common.Address{1})
+		b.SetExcessBlobs(0)
 		msg := types.BlobTxMessage{
 			Nonce: 0,
 			Gas:   500000,
@@ -3950,4 +3951,3 @@ func TestDataBlobTxs(t *testing.T) {
 		t.Fatalf("incorrect data hash written to state (want: %s, got: %s)", two, actual)
 	}
 }
-

core/beacon/types.go

@@ -78,6 +78,11 @@ func (b *BlockGen) SetDifficulty(diff *big.Int) {
 	b.header.Difficulty = diff
 }
 
+// SetExcessBlobs sets the excess_blobs field of the generated block.
+func (b *BlockGen) SetExcessBlobs(excessBlobs uint64) {
+	b.header.SetExcessBlobs(excessBlobs)
+}
+
 // AddTx adds a transaction to the generated block. If no coinbase has
 // been set, the block's coinbase is set to the zero address.
 //
@@ -135,6 +140,15 @@ func (b *BlockGen) BaseFee() *big.Int {
 	return new(big.Int).Set(b.header.BaseFee)
 }
 
+// ExcessBlobs returns the EIP-4844 excess blobs of the block being generated.
+func (b *BlockGen) ExcessBlobs() *uint64 {
+	v := new(uint64)
+	if b.header.ExcessBlobs != nil {
+		*v = *b.header.ExcessBlobs
+	}
+	return v
+}
+
 // AddUncheckedReceipt forcefully adds a receipts to the block without a
 // backing transaction.
 //