BEP-341: Validators can produce consecutive blocks

consensus/parlia/abi.go

@@ -1015,6 +1015,19 @@ const validatorSetABIBeforeLuban = `
       "stateMutability": "view",
       "type": "function"
     },
+    {
+      "inputs": [],
+      "name": "getTurnTerm",
+      "outputs": [
+        {
+          "internalType": "uint256",
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "stateMutability": "view",
+      "type": "function"
+    },
     {
       "inputs": [
         {

consensus/parlia/haberfork.go

@@ -0,0 +1,47 @@
+package parlia
+
+import (
+	"context"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/common/math"
+	"github.com/ethereum/go-ethereum/core/systemcontracts"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/internal/ethapi"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+func (p *Parlia) getTurnTerm(header *types.Header) (turnTerm *big.Int, err error) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	method := "getTurnTerm"
+	toAddress := common.HexToAddress(systemcontracts.ValidatorContract)
+	gas := (hexutil.Uint64)(uint64(math.MaxUint64 / 2))
+
+	data, err := p.validatorSetABI.Pack(method)
+	if err != nil {
+		log.Error("Unable to pack tx for getTurnTerm", "error", err)
+		return nil, err
+	}
+	msgData := (hexutil.Bytes)(data)
+
+	blockNr := rpc.BlockNumberOrHashWithHash(header.Hash(), false)
+	result, err := p.ethAPI.Call(ctx, ethapi.TransactionArgs{
+		Gas:  &gas,
+		To:   &toAddress,
+		Data: &msgData,
+	}, &blockNr, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := p.validatorSetABI.UnpackIntoInterface(&turnTerm, method, result); err != nil {
+		return nil, err
+	}
+
+	return turnTerm, nil
+}

consensus/parlia/parlia.go

@@ -54,10 +54,12 @@ const (
 
 	checkpointInterval = 1024        // Number of blocks after which to save the snapshot to the database
 	defaultEpochLength = uint64(100) // Default number of blocks of checkpoint to update validatorSet from contract
+	defaultTurnTerm    = uint64(1)   // Default consecutive number of blocks a validator receives priority for block production
 
 	extraVanity      = 32 // Fixed number of extra-data prefix bytes reserved for signer vanity
 	extraSeal        = 65 // Fixed number of extra-data suffix bytes reserved for signer seal
 	nextForkHashSize = 4  // Fixed number of extra-data suffix bytes reserved for nextForkHash.
+	turnTermSize     = 1  // Fixed number of extra-data suffix bytes reserved for turnTerm
 
 	validatorBytesLengthBeforeLuban = common.AddressLength
 	validatorBytesLength            = common.AddressLength + types.BLSPublicKeyLength
@@ -136,6 +138,10 @@ var (
 	// list of validators different than the one the local node calculated.
 	errMismatchingEpochValidators = errors.New("mismatching validator list on epoch block")
 
+	// errMismatchingEpochTurnTerm is returned if a sprint block contains a
+	// turn term different than the one the local node calculated.
+	errMismatchingEpochTurnTerm = errors.New("mismatching turn term on epoch block")
+
 	// errInvalidDifficulty is returned if the difficulty of a block is missing.
 	errInvalidDifficulty = errors.New("invalid difficulty")
 
@@ -365,6 +371,7 @@ func (p *Parlia) VerifyHeaders(chain consensus.ChainHeaderReader, headers []*typ
 // On luban fork, we introduce vote attestation into the header's extra field, so extra format is different from before.
 // Before luban fork: |---Extra Vanity---|---Validators Bytes (or Empty)---|---Extra Seal---|
 // After luban fork:  |---Extra Vanity---|---Validators Number and Validators Bytes (or Empty)---|---Vote Attestation (or Empty)---|---Extra Seal---|
+// After haber fork:  |---Extra Vanity---|---Validators Number and Validators Bytes (or Empty)---|---Turn Term (or Empty)---|---Vote Attestation (or Empty)---|---Extra Seal---|
 func getValidatorBytesFromHeader(header *types.Header, chainConfig *params.ChainConfig, parliaConfig *params.ParliaConfig) []byte {
 	if len(header.Extra) <= extraVanity+extraSeal {
 		return nil
@@ -381,11 +388,11 @@ func getValidatorBytesFromHeader(header *types.Header, chainConfig *params.Chain
 		return nil
 	}
 	num := int(header.Extra[extraVanity])
-	if num == 0 || len(header.Extra) <= extraVanity+extraSeal+num*validatorBytesLength {
-		return nil
-	}
 	start := extraVanity + validatorNumberSize
 	end := start + num*validatorBytesLength
+	if num == 0 || len(header.Extra) < end+extraSeal {
+		return nil
+	}
 	return header.Extra[start:end]
 }
 
@@ -404,11 +411,14 @@ func getVoteAttestationFromHeader(header *types.Header, chainConfig *params.Chai
 		attestationBytes = header.Extra[extraVanity : len(header.Extra)-extraSeal]
 	} else {
 		num := int(header.Extra[extraVanity])
-		if len(header.Extra) <= extraVanity+extraSeal+validatorNumberSize+num*validatorBytesLength {
-			return nil, nil
-		}
 		start := extraVanity + validatorNumberSize + num*validatorBytesLength
+		if chainConfig.IsHaber(header.Number, header.Time) {
+			start += turnTermSize
+		}
 		end := len(header.Extra) - extraSeal
+		if end <= start {
+			return nil, nil
+		}
 		attestationBytes = header.Extra[start:end]
 	}
 
@@ -884,6 +894,33 @@ func (p *Parlia) prepareValidators(header *types.Header) error {
 	return nil
 }
 
+func (p *Parlia) prepareTurnTerm(chain consensus.ChainHeaderReader, header *types.Header) error {
+	if header.Number.Uint64()%p.config.Epoch != 0 ||
+		!p.chainConfig.IsHaber(header.Number, header.Time) {
+		return nil
+	}
+
+	parent := chain.GetHeaderByHash(header.ParentHash)
+	if parent == nil {
+		return errors.New("parent not found")
+	}
+
+	if p.chainConfig.IsHaber(parent.Number, parent.Time) {
+		turnTerm, err := p.getTurnTerm(parent)
+		if err != nil {
+			return err
+		}
+		if turnTerm == nil {
+			return errors.New("unexpected error when getTurnTerm")
+		}
+		header.Extra = append(header.Extra, byte(int(turnTerm.Int64())))
+	} else {
+		header.Extra = append(header.Extra, byte(int(defaultTurnTerm)))
+	}
+
+	return nil
+}
+
 func (p *Parlia) assembleVoteAttestation(chain consensus.ChainHeaderReader, header *types.Header) error {
 	if !p.chainConfig.IsLuban(header.Number) || header.Number.Uint64() < 2 {
 		return nil
@@ -1015,6 +1052,9 @@ func (p *Parlia) Prepare(chain consensus.ChainHeaderReader, header *types.Header
 		return err
 	}
 
+	if err := p.prepareTurnTerm(chain, header); err != nil {
+		return err
+	}
 	// add extra seal space
 	header.Extra = append(header.Extra, make([]byte, extraSeal)...)
 
@@ -1065,6 +1105,40 @@ func (p *Parlia) verifyValidators(header *types.Header) error {
 	return nil
 }
 
+func (p *Parlia) verifyTurnTerm(chain consensus.ChainHeaderReader, header *types.Header) error {
+	if header.Number.Uint64()%p.config.Epoch != 0 ||
+		!p.chainConfig.IsHaber(header.Number, header.Time) {
+		return nil
+	}
+
+	turnTermFromHeader, err := parseTurnTerm(header, p.chainConfig, p.config)
+	if err != nil {
+		return err
+	}
+	if turnTermFromHeader != nil {
+		parent := chain.GetHeaderByHash(header.ParentHash)
+		if parent == nil {
+			return errors.New("parent not found")
+		}
+
+		if p.chainConfig.IsHaber(parent.Number, parent.Time) {
+			turnTermFromContract, err := p.getTurnTerm(parent)
+			if err != nil {
+				return err
+			}
+			if turnTermFromContract != nil && uint8(turnTermFromContract.Int64()) == *turnTermFromHeader {
+				return nil
+			}
+		} else {
+			if uint8(defaultTurnTerm) == *turnTermFromHeader {
+				return nil
+			}
+		}
+	}
+
+	return errMismatchingEpochTurnTerm
+}
+
 func (p *Parlia) distributeFinalityReward(chain consensus.ChainHeaderReader, state *state.StateDB, header *types.Header,
 	cx core.ChainContext, txs *[]*types.Transaction, receipts *[]*types.Receipt, systemTxs *[]*types.Transaction,
 	usedGas *uint64, mining bool) error {
@@ -1159,6 +1233,10 @@ func (p *Parlia) Finalize(chain consensus.ChainHeaderReader, header *types.Heade
 		return err
 	}
 
+	if err := p.verifyTurnTerm(chain, header); err != nil {
+		return err
+	}
+
 	cx := chainContext{Chain: chain, parlia: p}
 
 	parent := chain.GetHeaderByHash(header.ParentHash)
@@ -1185,7 +1263,7 @@ func (p *Parlia) Finalize(chain consensus.ChainHeaderReader, header *types.Heade
 		}
 	}
 	if header.Difficulty.Cmp(diffInTurn) != 0 {
-		spoiledVal := snap.supposeValidator()
+		spoiledVal := snap.inturnValidator()
 		signedRecently := false
 		if p.chainConfig.IsPlato(header.Number) {
 			signedRecently = snap.SignRecently(spoiledVal)
@@ -1276,7 +1354,7 @@ func (p *Parlia) FinalizeAndAssemble(chain consensus.ChainHeaderReader, header *
 		if err != nil {
 			return nil, nil, err
 		}
-		spoiledVal := snap.supposeValidator()
+		spoiledVal := snap.inturnValidator()
 		signedRecently := false
 		if p.chainConfig.IsPlato(header.Number) {
 			signedRecently = snap.SignRecently(spoiledVal)
@@ -1905,26 +1983,15 @@ func (p *Parlia) backOffTime(snap *Snapshot, header *types.Header, val common.Ad
 		delay := initialBackOffTime
 		validators := snap.validators()
 		if p.chainConfig.IsPlanck(header.Number) {
-			// reverse the key/value of snap.Recents to get recentsMap
-			recentsMap := make(map[common.Address]uint64, len(snap.Recents))
-			bound := uint64(0)
-			if n, limit := header.Number.Uint64(), uint64(len(validators)/2+1); n > limit {
-				bound = n - limit
-			}
-			for seen, recent := range snap.Recents {
-				if seen <= bound {
-					continue
-				}
-				recentsMap[recent] = seen
-			}
+			counts := snap.countRecents()
 
 			// The backOffTime does not matter when a validator has signed recently.
-			if _, ok := recentsMap[val]; ok {
+			if snap.signRecentlyByCounts(val, counts) {
 				return 0
 			}
 
-			inTurnAddr := validators[(snap.Number+1)%uint64(len(validators))]
-			if _, ok := recentsMap[inTurnAddr]; ok {
+			inTurnAddr := snap.inturnValidator()
+			if snap.signRecentlyByCounts(inTurnAddr, counts) {
 				log.Debug("in turn validator has recently signed, skip initialBackOffTime",
 					"inTurnAddr", inTurnAddr)
 				delay = 0
@@ -1933,7 +2000,7 @@ func (p *Parlia) backOffTime(snap *Snapshot, header *types.Header, val common.Ad
 			// Exclude the recently signed validators
 			temp := make([]common.Address, 0, len(validators))
 			for _, addr := range validators {
-				if _, ok := recentsMap[addr]; ok {
+				if snap.signRecentlyByCounts(addr, counts) {
 					continue
 				}
 				temp = append(temp, addr)