Add support for syncing pre-fork blocks

consensus/beacon/consensus.go

@@ -80,19 +80,21 @@ func (beacon *Beacon) Author(header *types.Header) (common.Address, error) {
 
 // VerifyHeader checks whether a header conforms to the consensus rules of the
 // stock Ethereum consensus engine.
-func (beacon *Beacon) VerifyHeader(chain consensus.ChainHeaderReader, header *types.Header) error {
+func (beacon *Beacon) VerifyHeader(chain consensus.ChainHeaderReader, header *types.Header, parent *types.Header) error {
 	reached, err := IsTTDReached(chain, header.ParentHash, header.Number.Uint64()-1)
 	if err != nil {
 		return err
 	}
 	if !reached {
-		return beacon.ethone.VerifyHeader(chain, header)
+		return beacon.ethone.VerifyHeader(chain, header, parent)
 	}
 	// Short circuit if the parent is not known
-	parent := chain.GetHeader(header.ParentHash, header.Number.Uint64()-1)
+	if parent == nil {
+		parent = chain.GetHeader(header.ParentHash, header.Number.Uint64()-1)
 		if parent == nil {
 			return consensus.ErrUnknownAncestor
 		}
+	}
 	// Sanity checks passed, do a proper verification
 	return beacon.verifyHeader(chain, header, parent)
 }
@@ -128,21 +130,16 @@ func (beacon *Beacon) splitHeaders(chain consensus.ChainHeaderReader, headers []
 	var (
 		preHeaders  = headers
 		postHeaders []*types.Header
-		td          = new(big.Int).Set(ptd)
-		tdPassed    bool
 	)
 	for i, header := range headers {
-		if tdPassed {
+		// PulseChain Special Case:
+		// Partition based on header difficulty (IsPoSHeader) instead of TTD being reached
+		// so we can properly handle ETH Beacon blocks below the increased PulseChain TTD.
+		if beacon.IsPoSHeader(header) {
 			preHeaders = headers[:i]
 			postHeaders = headers[i:]
 			break
 		}
-		td = td.Add(td, header.Difficulty)
-		if td.Cmp(ttd) >= 0 {
-			// This is the last PoW header, it still belongs to
-			// the preHeaders, so we cannot split+break yet.
-			tdPassed = true
-		}
 	}
 	return preHeaders, postHeaders, nil
 }
@@ -151,31 +148,73 @@ func (beacon *Beacon) splitHeaders(chain consensus.ChainHeaderReader, headers []
 // concurrently. The method returns a quit channel to abort the operations and
 // a results channel to retrieve the async verifications.
 // VerifyHeaders expect the headers to be ordered and continuous.
+//
+// Normal Cases:
+//  1. x * POW blocks
+//  2. x * POS blocks
+//  3. x * POW blocks => y * POS blocks
+//
+// Special Cases for PulseChain:
+//  4. x * POS blocks[eth] => POW fork block[pls]
+//  5. x * POS blocks[eth] => POW fork block[pls] => y * POS blocks[pls]
 func (beacon *Beacon) VerifyHeaders(chain consensus.ChainHeaderReader, headers []*types.Header) (chan<- struct{}, <-chan error) {
 	preHeaders, postHeaders, err := beacon.splitHeaders(chain, headers)
 	if err != nil {
 		return make(chan struct{}), errOut(len(headers), err)
 	}
+	// Case 1
 	if len(postHeaders) == 0 {
 		return beacon.ethone.VerifyHeaders(chain, headers)
 	}
-	if len(preHeaders) == 0 {
+	chainCfg := chain.Config()
+	primordialPulseIndex := 0
+	if chainCfg.PrimordialPulseAhead(postHeaders[0].Number) && !chainCfg.PrimordialPulseAhead(postHeaders[len(postHeaders)-1].Number) {
+		primordialPulseIndex = int(new(big.Int).Sub(chainCfg.PrimordialPulseBlock, postHeaders[0].Number).Uint64())
+	}
+	// Case 2
+	if len(preHeaders) == 0 && primordialPulseIndex == 0 {
 		return beacon.verifyHeaders(chain, headers, nil)
 	}
 	// The transition point exists in the middle, separate the headers
-	// into two batches and apply different verification rules for them.
+	// into batches and apply different verification rules for them.
 	var (
 		abort   = make(chan struct{})
 		results = make(chan error, len(headers))
 	)
 	go func() {
 		var (
-			old, new, out      = 0, len(preHeaders), 0
+			oldIdx, out          = 0, 0
 			errors               = make([]error, len(headers))
 			done                 = make([]bool, len(headers))
 			oldDone, oldResult   = beacon.ethone.VerifyHeaders(chain, preHeaders)
-			newDone, newResult = beacon.verifyHeaders(chain, postHeaders, preHeaders[len(preHeaders)-1])
+			lastPowHeader        *types.Header
+			pulseChainForkHeader *types.Header
+			preforkPosIdx        = len(preHeaders)
+			preforkPosHeaders    = postHeaders
+			postforkPosIdx       = len(headers)
+			postforkPosHeaders   = []*types.Header{}
 		)
+		// Case 3
+		if len(preHeaders) > 0 {
+			lastPowHeader = preHeaders[len(preHeaders)-1]
+		}
+		// Handle fork partitioning and verification for cases 4 and 5
+		if primordialPulseIndex > 0 {
+			preforkPosHeaders = postHeaders[:primordialPulseIndex]
+			pulseChainForkHeader = postHeaders[primordialPulseIndex]
+
+			// Verify the fork block
+			forkBlockResult := beacon.ethone.VerifyHeader(chain, pulseChainForkHeader, postHeaders[primordialPulseIndex-1])
+			forkBlockIdx := preforkPosIdx + len(preforkPosHeaders)
+			errors[forkBlockIdx], done[forkBlockIdx] = forkBlockResult, true
+
+			// Can be empty in case 4
+			postforkPosHeaders = postHeaders[primordialPulseIndex+1:]
+			postforkPosIdx = forkBlockIdx + 1
+		}
+		preforkPosDone, preforkPosResult := beacon.verifyHeaders(chain, preforkPosHeaders, lastPowHeader)
+		postforkPosDone, postforkPosResult := beacon.verifyHeaders(chain, postforkPosHeaders, pulseChainForkHeader)
+
 		// Collect the results
 		for {
 			for ; done[out]; out++ {
@@ -186,16 +225,20 @@ func (beacon *Beacon) VerifyHeaders(chain consensus.ChainHeaderReader, headers [
 			}
 			select {
 			case err := <-oldResult:
-				if !done[old] { // skip TTD-verified failures
-					errors[old], done[old] = err, true
+				if !done[oldIdx] { // skip TTD-verified failures
+					errors[oldIdx], done[oldIdx] = err, true
 				}
-				old++
-			case err := <-newResult:
-				errors[new], done[new] = err, true
-				new++
+				oldIdx++
+			case err := <-preforkPosResult:
+				errors[preforkPosIdx], done[preforkPosIdx] = err, true
+				preforkPosIdx++
+			case err := <-postforkPosResult:
+				errors[postforkPosIdx], done[postforkPosIdx] = err, true
+				postforkPosIdx++
 			case <-abort:
 				close(oldDone)
-				close(newDone)
+				close(preforkPosDone)
+				close(postforkPosDone)
 				return
 			}
 		}

consensus/clique/clique.go

@@ -216,8 +216,12 @@ func (c *Clique) Author(header *types.Header) (common.Address, error) {
 }
 
 // VerifyHeader checks whether a header conforms to the consensus rules.
-func (c *Clique) VerifyHeader(chain consensus.ChainHeaderReader, header *types.Header) error {
-	return c.verifyHeader(chain, header, nil)
+func (c *Clique) VerifyHeader(chain consensus.ChainHeaderReader, header *types.Header, parent *types.Header) error {
+	var parentHeaders []*types.Header
+	if parent != nil {
+		parentHeaders = []*types.Header{parent}
+	}
+	return c.verifyHeader(chain, header, parentHeaders)
 }
 
 // VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers. The

consensus/consensus.go

@@ -67,7 +67,7 @@ type Engine interface {
 
 	// VerifyHeader checks whether a header conforms to the consensus rules of a
 	// given engine.
-	VerifyHeader(chain ChainHeaderReader, header *types.Header) error
+	VerifyHeader(chain ChainHeaderReader, header *types.Header, parent *types.Header) error
 
 	// VerifyHeaders is similar to VerifyHeader, but verifies a batch of headers
 	// concurrently. The method returns a quit channel to abort the operations and

consensus/ethash/consensus.go

@@ -100,16 +100,18 @@ func (ethash *Ethash) Author(header *types.Header) (common.Address, error) {
 
 // VerifyHeader checks whether a header conforms to the consensus rules of the
 // stock Ethereum ethash engine.
-func (ethash *Ethash) VerifyHeader(chain consensus.ChainHeaderReader, header *types.Header) error {
+func (ethash *Ethash) VerifyHeader(chain consensus.ChainHeaderReader, header *types.Header, parent *types.Header) error {
 	// Short circuit if the header is known, or its parent not
 	number := header.Number.Uint64()
 	if chain.GetHeader(header.Hash(), number) != nil {
 		return nil
 	}
-	parent := chain.GetHeader(header.ParentHash, number-1)
+	if parent == nil {
+		parent = chain.GetHeader(header.ParentHash, number-1)
 		if parent == nil {
 			return consensus.ErrUnknownAncestor
 		}
+	}
 	// Sanity checks passed, do a proper verification
 	return ethash.verifyHeader(chain, header, parent, false, time.Now().Unix())
 }

core/blockchain.go

@@ -410,7 +410,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, genesis *Genesis
 	// The first thing the node will do is reconstruct the verification data for
 	// the head block (ethash cache or clique voting snapshot). Might as well do
 	// it in advance.
-	bc.engine.VerifyHeader(bc, bc.CurrentHeader())
+	bc.engine.VerifyHeader(bc, bc.CurrentHeader(), nil)
 
 	// Check the current state of the block hashes and make sure that we do not have any of the bad blocks in our chain
 	for hash := range BadHashes {

core/blockchain_test.go

@@ -149,7 +149,7 @@ func testFork(t *testing.T, blockchain *BlockChain, i, n int, full bool, compara
 func testBlockChainImport(chain types.Blocks, blockchain *BlockChain) error {
 	for _, block := range chain {
 		// Try and process the block
-		err := blockchain.engine.VerifyHeader(blockchain, block.Header())
+		err := blockchain.engine.VerifyHeader(blockchain, block.Header(), nil)
 		if err == nil {
 			err = blockchain.validator.ValidateBody(block)
 		}
@@ -188,7 +188,7 @@ func testBlockChainImport(chain types.Blocks, blockchain *BlockChain) error {
 func testHeaderChainImport(chain []*types.Header, blockchain *BlockChain) error {
 	for _, header := range chain {
 		// Try and validate the header
-		if err := blockchain.engine.VerifyHeader(blockchain, header); err != nil {
+		if err := blockchain.engine.VerifyHeader(blockchain, header, nil); err != nil {
 			return err
 		}
 		// Manually insert the header into the database, but don't reorganise (allows subsequent testing)

core/forkchoice.go

@@ -108,6 +108,10 @@ func (f *ForkChoice) ReorgNeeded(current *types.Header, extern *types.Header) (b
 			currentPreserve, externPreserve = f.preserve(current), f.preserve(extern)
 		}
 		reorg = !currentPreserve && (externPreserve || f.rand.Float64() < 0.5)
+	} else if f.chain.Config().PrimordialPulseAhead(extern.Number) {
+		// Pre-fork ethereum mainnet pos blocks have a difficulty of 0.
+		// These blocks should be accepted onto the chain head.
+		reorg = true
 	}
 	return reorg, nil
 }

core/types/transaction_signing.go

@@ -39,15 +39,22 @@ type sigCache struct {
 // MakeSigner returns a Signer based on the given chain config and block number.
 func MakeSigner(config *params.ChainConfig, blockNumber *big.Int, blockTime uint64) Signer {
 	var signer Signer
+
+	chainID := config.ChainID
+	if config.PrimordialPulseAhead(blockNumber) {
+		// Use ethereum mainnet chainid for pre-fork transactions
+		chainID = big.NewInt(1)
+	}
+
 	switch {
 	case config.IsCancun(blockNumber, blockTime):
 		signer = NewCancunSigner(config.ChainID)
 	case config.IsLondon(blockNumber):
-		signer = NewLondonSigner(config.ChainID)
+		signer = NewLondonSigner(chainID)
 	case config.IsBerlin(blockNumber):
-		signer = NewEIP2930Signer(config.ChainID)
+		signer = NewEIP2930Signer(chainID)
 	case config.IsEIP155(blockNumber):
-		signer = NewEIP155Signer(config.ChainID)
+		signer = NewEIP155Signer(chainID)
 	case config.IsHomestead(blockNumber):
 		signer = HomesteadSigner{}
 	default:

core/vm/evm.go

@@ -137,13 +137,25 @@ func NewEVM(blockCtx BlockContext, txCtx TxContext, statedb StateDB, chainConfig
 			blockCtx.BlobBaseFee = new(big.Int)
 		}
 	}
+
+	// FlexChainConfig allows for processing prefork transactions on PulseChain
+	flexChainConfig := chainConfig
+	if chainConfig.PrimordialPulseAhead(blockCtx.BlockNumber) {
+		// Create a shallow of chainConfig struct and set to ethereum mainnet
+		chainCfgCpy := *chainConfig
+		chainCfgCpy.ChainID = big.NewInt(1)
+
+		// Use the new chainCfgCpy
+		flexChainConfig = &chainCfgCpy
+	}
+
 	evm := &EVM{
 		Context:     blockCtx,
 		TxContext:   txCtx,
 		StateDB:     statedb,
 		Config:      config,
-		chainConfig: chainConfig,
-		chainRules:  chainConfig.Rules(blockCtx.BlockNumber, blockCtx.Random != nil, blockCtx.Time),
+		chainConfig: flexChainConfig,
+		chainRules:  flexChainConfig.Rules(blockCtx.BlockNumber, blockCtx.Random != nil, blockCtx.Time),
 	}
 	evm.interpreter = NewEVMInterpreter(evm)
 	return evm

eth/handler.go

@@ -215,7 +215,7 @@ func newHandler(config *handlerConfig) (*handler, error) {
 				return errors.New("unexpected post-merge header")
 			}
 		}
-		return h.chain.Engine().VerifyHeader(h.chain, header)
+		return h.chain.Engine().VerifyHeader(h.chain, header, nil)
 	}
 	heighter := func() uint64 {
 		return h.chain.CurrentBlock().Number.Uint64()

params/config.go

@@ -591,6 +591,11 @@ func (c *ChainConfig) IsPrimordialPulseBlock(num *big.Int) bool {
 	return c.PrimordialPulseBlock != nil && c.PrimordialPulseBlock.Cmp(num) == 0
 }
 
+// Returns true if there is a PrimordialPulse block in the future.
+func (c *ChainConfig) PrimordialPulseAhead(num *big.Int) bool {
+	return c.PrimordialPulseBlock != nil && c.PrimordialPulseBlock.Cmp(num) > 0
+}
+
 // CheckCompatible checks whether scheduled fork transitions have been imported
 // with a mismatching chain configuration.
 func (c *ChainConfig) CheckCompatible(newcfg *ChainConfig, height uint64, time uint64) *ConfigCompatError {