support fork id in header; elegant upgrade

consensus/parlia/parlia.go

@@ -3,6 +3,7 @@ package parlia
 import (
 	"bytes"
 	"context"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"io"
@@ -25,6 +26,7 @@ import (
 	"github.com/ethereum/go-ethereum/consensus"
 	"github.com/ethereum/go-ethereum/consensus/misc"
 	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/forkid"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/systemcontracts"
 	"github.com/ethereum/go-ethereum/core/types"
@@ -45,8 +47,9 @@ 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
 
-	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
+	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.
 
 	validatorBytesLength = common.AddressLength
 	wiggleTime           = uint64(1) // second, Random delay (per signer) to allow concurrent signers
@@ -188,7 +191,8 @@ func ParliaRLP(header *types.Header, chainId *big.Int) []byte {
 type Parlia struct {
 	chainConfig *params.ChainConfig  // Chain config
 	config      *params.ParliaConfig // Consensus engine configuration parameters for parlia consensus
-	db          ethdb.Database       // Database to store and retrieve snapshot checkpoints
+	genesisHash common.Hash
+	db          ethdb.Database // Database to store and retrieve snapshot checkpoints
 
 	recentSnaps *lru.ARCCache // Snapshots for recent block to speed up
 	signatures  *lru.ARCCache // Signatures of recent blocks to speed up mining
@@ -214,6 +218,7 @@ func New(
 	chainConfig *params.ChainConfig,
 	db ethdb.Database,
 	ethAPI *ethapi.PublicBlockChainAPI,
+	genesisHash common.Hash,
 ) *Parlia {
 	// get parlia config
 	parliaConfig := chainConfig.Parlia
@@ -243,6 +248,7 @@ func New(
 	c := &Parlia{
 		chainConfig:     chainConfig,
 		config:          parliaConfig,
+		genesisHash:     genesisHash,
 		db:              db,
 		ethAPI:          ethAPI,
 		recentSnaps:     recentSnaps,
@@ -599,10 +605,12 @@ func (p *Parlia) Prepare(chain consensus.ChainReader, header *types.Header) erro
 	header.Difficulty = CalcDifficulty(snap, p.val)
 
 	// Ensure the extra data has all it's components
-	if len(header.Extra) < extraVanity {
-		header.Extra = append(header.Extra, bytes.Repeat([]byte{0x00}, extraVanity-len(header.Extra))...)
+	if len(header.Extra) < extraVanity-nextForkHashSize {
+		header.Extra = append(header.Extra, bytes.Repeat([]byte{0x00}, extraVanity-nextForkHashSize-len(header.Extra))...)
 	}
-	header.Extra = header.Extra[:extraVanity]
+	header.Extra = header.Extra[:extraVanity-nextForkHashSize]
+	nextForkHash := forkid.NextForkHash(p.chainConfig, p.genesisHash, number)
+	header.Extra = append(header.Extra, nextForkHash[:]...)
 
 	if number%p.config.Epoch == 0 {
 		newValidators, err := p.getCurrentValidators(header.ParentHash)
@@ -638,6 +646,16 @@ func (p *Parlia) Prepare(chain consensus.ChainReader, header *types.Header) erro
 // rewards given.
 func (p *Parlia) Finalize(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs *[]*types.Transaction,
 	uncles []*types.Header, receipts *[]*types.Receipt, systemTxs *[]*types.Transaction, usedGas *uint64) error {
+	// warn if not in majority fork
+	number := header.Number.Uint64()
+	snap, err := p.snapshot(chain, number-1, header.ParentHash, nil)
+	if err != nil {
+		panic(err)
+	}
+	nextForkHash := forkid.NextForkHash(p.chainConfig, p.genesisHash, number)
+	if !snap.isMajorityFork(hex.EncodeToString(nextForkHash[:])) {
+		log.Warn("there is a possible fork, and your client is not the majority. Please check...", "nextForkHash", hex.EncodeToString(nextForkHash[:]))
+	}
 	// If the block is a epoch end block, verify the validator list
 	// The verification can only be done when the state is ready, it can't be done in VerifyHeader.
 	if header.Number.Uint64()%p.config.Epoch == 0 {
@@ -666,11 +684,6 @@ func (p *Parlia) Finalize(chain consensus.ChainReader, header *types.Header, sta
 		}
 	}
 	if header.Difficulty.Cmp(diffInTurn) != 0 {
-		number := header.Number.Uint64()
-		snap, err := p.snapshot(chain, number-1, header.ParentHash, nil)
-		if err != nil {
-			panic(err)
-		}
 		spoiledVal := snap.supposeValidator()
 		signedRecently := false
 		for _, recent := range snap.Recents {
@@ -689,7 +702,7 @@ func (p *Parlia) Finalize(chain consensus.ChainReader, header *types.Header, sta
 		}
 	}
 	val := header.Coinbase
-	err := p.distributeIncoming(val, state, header, cx, txs, receipts, systemTxs, usedGas, false)
+	err = p.distributeIncoming(val, state, header, cx, txs, receipts, systemTxs, usedGas, false)
 	if err != nil {
 		panic(err)
 	}

consensus/parlia/snapshot.go

@@ -18,6 +18,7 @@ package parlia
 
 import (
 	"bytes"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"math/big"
@@ -38,10 +39,11 @@ type Snapshot struct {
 	ethAPI   *ethapi.PublicBlockChainAPI
 	sigCache *lru.ARCCache // Cache of recent block signatures to speed up ecrecover
 
-	Number     uint64                      `json:"number"`     // Block number where the snapshot was created
-	Hash       common.Hash                 `json:"hash"`       // Block hash where the snapshot was created
-	Validators map[common.Address]struct{} `json:"validators"` // Set of authorized validators at this moment
-	Recents    map[uint64]common.Address   `json:"recents"`    // Set of recent validators for spam protections
+	Number           uint64                      `json:"number"`             // Block number where the snapshot was created
+	Hash             common.Hash                 `json:"hash"`               // Block hash where the snapshot was created
+	Validators       map[common.Address]struct{} `json:"validators"`         // Set of authorized validators at this moment
+	Recents          map[uint64]common.Address   `json:"recents"`            // Set of recent validators for spam protections
+	RecentForkHashes map[uint64]string           `json:"recent_fork_hashes"` // Set of recent forkHash
 }
 
 // newSnapshot creates a new snapshot with the specified startup parameters. This
@@ -56,13 +58,14 @@ func newSnapshot(
 	ethAPI *ethapi.PublicBlockChainAPI,
 ) *Snapshot {
 	snap := &Snapshot{
-		config:     config,
-		ethAPI:     ethAPI,
-		sigCache:   sigCache,
-		Number:     number,
-		Hash:       hash,
-		Recents:    make(map[uint64]common.Address),
-		Validators: make(map[common.Address]struct{}),
+		config:           config,
+		ethAPI:           ethAPI,
+		sigCache:         sigCache,
+		Number:           number,
+		Hash:             hash,
+		Recents:          make(map[uint64]common.Address),
+		RecentForkHashes: make(map[uint64]string),
+		Validators:       make(map[common.Address]struct{}),
 	}
 	for _, v := range validators {
 		snap.Validators[v] = struct{}{}
@@ -106,13 +109,14 @@ func (s *Snapshot) store(db ethdb.Database) error {
 // copy creates a deep copy of the snapshot
 func (s *Snapshot) copy() *Snapshot {
 	cpy := &Snapshot{
-		config:     s.config,
-		ethAPI:     s.ethAPI,
-		sigCache:   s.sigCache,
-		Number:     s.Number,
-		Hash:       s.Hash,
-		Validators: make(map[common.Address]struct{}),
-		Recents:    make(map[uint64]common.Address),
+		config:           s.config,
+		ethAPI:           s.ethAPI,
+		sigCache:         s.sigCache,
+		Number:           s.Number,
+		Hash:             s.Hash,
+		Validators:       make(map[common.Address]struct{}),
+		Recents:          make(map[uint64]common.Address),
+		RecentForkHashes: make(map[uint64]string),
 	}
 
 	for v := range s.Validators {
@@ -121,9 +125,22 @@ func (s *Snapshot) copy() *Snapshot {
 	for block, v := range s.Recents {
 		cpy.Recents[block] = v
 	}
+	for block, id := range s.RecentForkHashes {
+		cpy.RecentForkHashes[block] = id
+	}
 	return cpy
 }
 
+func (s *Snapshot) isMajorityFork(forkHash string) bool {
+	ally := 0
+	for _, h := range s.RecentForkHashes {
+		if h == forkHash {
+			ally++
+		}
+	}
+	return ally > len(s.RecentForkHashes)/2
+}
+
 func (s *Snapshot) apply(headers []*types.Header, chain consensus.ChainReader, parents []*types.Header, chainId *big.Int) (*Snapshot, error) {
 	// Allow passing in no headers for cleaner code
 	if len(headers) == 0 {
@@ -153,6 +170,9 @@ func (s *Snapshot) apply(headers []*types.Header, chain consensus.ChainReader, p
 		if limit := uint64(len(snap.Validators)/2 + 1); number >= limit {
 			delete(snap.Recents, number-limit)
 		}
+		if limit := uint64(len(snap.Validators)); number >= limit {
+			delete(snap.RecentForkHashes, number-limit)
+		}
 		// Resolve the authorization key and check against signers
 		validator, err := ecrecover(header, s.sigCache, chainId)
 		if err != nil {
@@ -191,8 +211,10 @@ func (s *Snapshot) apply(headers []*types.Header, chain consensus.ChainReader, p
 					delete(snap.Recents, number-uint64(newLimit)-uint64(i))
 				}
 			}
+			snap.RecentForkHashes = make(map[uint64]string, 0)
 			snap.Validators = newVals
 		}
+		snap.RecentForkHashes[number] = hex.EncodeToString(header.Extra[extraVanity-nextForkHashSize : extraVanity])
 	}
 	snap.Number += uint64(len(headers))
 	snap.Hash = headers[len(headers)-1].Hash()

core/forkid/forkid.go

@@ -62,6 +62,28 @@ func NewID(chain *core.BlockChain) ID {
 	)
 }
 
+func NextForkHash(config *params.ChainConfig, genesis common.Hash, head uint64) [4]byte {
+	// Calculate the starting checksum from the genesis hash
+	hash := crc32.ChecksumIEEE(genesis[:])
+
+	// Calculate the current fork checksum and the next fork block
+	var next uint64
+	for _, fork := range gatherForks(config) {
+		if fork <= head {
+			// Fork already passed, checksum the previous hash and the fork number
+			hash = checksumUpdate(hash, fork)
+			continue
+		}
+		next = fork
+		break
+	}
+	if next == 0 {
+		return checksumToBytes(hash)
+	} else {
+		return checksumToBytes(checksumUpdate(hash, next))
+	}
+}
+
 // newID is the internal version of NewID, which takes extracted values as its
 // arguments instead of a chain. The reason is to allow testing the IDs without
 // having to simulate an entire blockchain.

eth/backend.go

@@ -158,7 +158,7 @@ func New(ctx *node.ServiceContext, config *Config) (*Ethereum, error) {
 
 	eth.APIBackend = &EthAPIBackend{ctx.ExtRPCEnabled(), eth, nil}
 	ethAPI := ethapi.NewPublicBlockChainAPI(eth.APIBackend)
-	eth.engine = CreateConsensusEngine(ctx, chainConfig, &config.Ethash, config.Miner.Notify, config.Miner.Noverify, chainDb, ethAPI)
+	eth.engine = CreateConsensusEngine(ctx, chainConfig, &config.Ethash, config.Miner.Notify, config.Miner.Noverify, chainDb, ethAPI, genesisHash)
 
 	bcVersion := rawdb.ReadDatabaseVersion(chainDb)
 	var dbVer = "<nil>"
@@ -243,21 +243,21 @@ func makeExtraData(extra []byte) []byte {
 			runtime.GOOS,
 		})
 	}
-	if uint64(len(extra)) > params.MaximumExtraDataSize {
-		log.Warn("Miner extra data exceed limit", "extra", hexutil.Bytes(extra), "limit", params.MaximumExtraDataSize)
+	if uint64(len(extra)) > params.MaximumExtraDataSize-params.ForkIDSize {
+		log.Warn("Miner extra data exceed limit", "extra", hexutil.Bytes(extra), "limit", params.MaximumExtraDataSize-params.ForkIDSize)
 		extra = nil
 	}
 	return extra
 }
 
 // CreateConsensusEngine creates the required type of consensus engine instance for an Ethereum service
-func CreateConsensusEngine(ctx *node.ServiceContext, chainConfig *params.ChainConfig, config *ethash.Config, notify []string, noverify bool, db ethdb.Database, ee *ethapi.PublicBlockChainAPI) consensus.Engine {
+func CreateConsensusEngine(ctx *node.ServiceContext, chainConfig *params.ChainConfig, config *ethash.Config, notify []string, noverify bool, db ethdb.Database, ee *ethapi.PublicBlockChainAPI, genesisHash common.Hash) consensus.Engine {
 	// If proof-of-authority is requested, set it up
 	if chainConfig.Clique != nil {
 		return clique.New(chainConfig.Clique, db)
 	}
 	if chainConfig.Parlia != nil {
-		return parlia.New(chainConfig, db, ee)
+		return parlia.New(chainConfig, db, ee, genesisHash)
 	}
 	// Otherwise assume proof-of-work
 	switch config.PowMode {

les/client.go

@@ -102,7 +102,7 @@ func New(ctx *node.ServiceContext, config *eth.Config) (*LightEthereum, error) {
 		eventMux:       ctx.EventMux,
 		reqDist:        newRequestDistributor(peers, &mclock.System{}),
 		accountManager: ctx.AccountManager,
-		engine:         eth.CreateConsensusEngine(ctx, chainConfig, &config.Ethash, nil, false, chainDb, nil),
+		engine:         eth.CreateConsensusEngine(ctx, chainConfig, &config.Ethash, nil, false, chainDb, nil, genesisHash),
 		bloomRequests:  make(chan chan *bloombits.Retrieval),
 		bloomIndexer:   eth.NewBloomIndexer(chainDb, params.BloomBitsBlocksClient, params.HelperTrieConfirmations),
 		serverPool:     newServerPool(chainDb, config.UltraLightServers),

params/protocol_params.go

@@ -24,6 +24,7 @@ const (
 	GenesisGasLimit      uint64 = 4712388 // Gas limit of the Genesis block.
 
 	MaximumExtraDataSize  uint64 = 32     // Maximum size extra data may be after Genesis.
+	ForkIDSize            uint64 = 4      // The length of fork id
 	ExpByteGas            uint64 = 10     // Times ceil(log256(exponent)) for the EXP instruction.
 	SloadGas              uint64 = 50     // Multiplied by the number of 32-byte words that are copied (round up) for any *COPY operation and added.
 	CallValueTransferGas  uint64 = 9000   // Paid for CALL when the value transfer is non-zero.