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author | Péter Szilágyi <peterke@gmail.com> | 2017-04-05 06:16:29 +0800 |
---|---|---|
committer | Felix Lange <fjl@users.noreply.github.com> | 2017-04-05 06:16:29 +0800 |
commit | 09777952ee476ff80d4b6e63b5041ff5ca0e441b (patch) | |
tree | e85320f88f548201e3476b3e7095e96fd071617b /core/block_validator.go | |
parent | e50a5b77712d891ff409aa942a5cbc24e721b332 (diff) | |
download | dexon-09777952ee476ff80d4b6e63b5041ff5ca0e441b.tar.gz dexon-09777952ee476ff80d4b6e63b5041ff5ca0e441b.tar.zst dexon-09777952ee476ff80d4b6e63b5041ff5ca0e441b.zip |
core, consensus: pluggable consensus engines (#3817)
This commit adds pluggable consensus engines to go-ethereum. In short, it
introduces a generic consensus interface, and refactors the entire codebase to
use this interface.
Diffstat (limited to 'core/block_validator.go')
-rw-r--r-- | core/block_validator.go | 275 |
1 files changed, 15 insertions, 260 deletions
diff --git a/core/block_validator.go b/core/block_validator.go index f93a9f40b..00457dd7a 100644 --- a/core/block_validator.go +++ b/core/block_validator.go @@ -19,22 +19,12 @@ package core import ( "fmt" "math/big" - "time" - "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/common/math" + "github.com/ethereum/go-ethereum/consensus" "github.com/ethereum/go-ethereum/core/state" "github.com/ethereum/go-ethereum/core/types" - "github.com/ethereum/go-ethereum/log" "github.com/ethereum/go-ethereum/params" - "github.com/ethereum/go-ethereum/pow" - "gopkg.in/fatih/set.v0" -) - -var ( - ExpDiffPeriod = big.NewInt(100000) - big10 = big.NewInt(10) - bigMinus99 = big.NewInt(-99) ) // BlockValidator is responsible for validating block headers, uncles and @@ -44,30 +34,24 @@ var ( type BlockValidator struct { config *params.ChainConfig // Chain configuration options bc *BlockChain // Canonical block chain - Pow pow.PoW // Proof of work used for validating + engine consensus.Engine // Consensus engine used for validating } // NewBlockValidator returns a new block validator which is safe for re-use -func NewBlockValidator(config *params.ChainConfig, blockchain *BlockChain, pow pow.PoW) *BlockValidator { +func NewBlockValidator(config *params.ChainConfig, blockchain *BlockChain, engine consensus.Engine) *BlockValidator { validator := &BlockValidator{ config: config, - Pow: pow, + engine: engine, bc: blockchain, } return validator } -// ValidateBlock validates the given block's header and uncles and verifies the -// the block header's transaction and uncle roots. -// -// ValidateBlock does not validate the header's pow. The pow work validated -// separately so we can process them in parallel. -// -// ValidateBlock also validates and makes sure that any previous state (or present) -// state that might or might not be present is checked to make sure that fast -// sync has done it's job proper. This prevents the block validator from accepting -// false positives where a header is present but the state is not. -func (v *BlockValidator) ValidateBlock(block *types.Block) error { +// ValidateBody validates the given block's uncles and verifies the the block +// header's transaction and uncle roots. The headers are assumed to be already +// validated at this point. +func (v *BlockValidator) ValidateBody(block *types.Block) error { + // Check whether the block's known, and if not, that it's linkable if v.bc.HasBlock(block.Hash()) { if _, err := state.New(block.Root(), v.bc.chainDb); err == nil { return &KnownBlockError{block.Number(), block.Hash()} @@ -80,30 +64,17 @@ func (v *BlockValidator) ValidateBlock(block *types.Block) error { if _, err := state.New(parent.Root(), v.bc.chainDb); err != nil { return ParentError(block.ParentHash()) } - + // Header validity is known at this point, check the uncles and transactions header := block.Header() - // validate the block header - if err := ValidateHeader(v.config, v.Pow, header, parent.Header(), false, false); err != nil { + if err := v.engine.VerifyUncles(v.bc, block); err != nil { return err } - // verify the uncles are correctly rewarded - if err := v.VerifyUncles(block, parent); err != nil { - return err + if hash := types.CalcUncleHash(block.Uncles()); hash != header.UncleHash { + return fmt.Errorf("uncle root hash mismatch: have %x, want %x", hash, header.UncleHash) } - - // Verify UncleHash before running other uncle validations - unclesSha := types.CalcUncleHash(block.Uncles()) - if unclesSha != header.UncleHash { - return fmt.Errorf("invalid uncles root hash (remote: %x local: %x)", header.UncleHash, unclesSha) - } - - // The transactions Trie's root (R = (Tr [[i, RLP(T1)], [i, RLP(T2)], ... [n, RLP(Tn)]])) - // can be used by light clients to make sure they've received the correct Txs - txSha := types.DeriveSha(block.Transactions()) - if txSha != header.TxHash { - return fmt.Errorf("invalid transaction root hash (remote: %x local: %x)", header.TxHash, txSha) + if hash := types.DeriveSha(block.Transactions()); hash != header.TxHash { + return fmt.Errorf("transaction root hash mismatch: have %x, want %x", hash, header.TxHash) } - return nil } @@ -135,222 +106,6 @@ func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *stat return nil } -// VerifyUncles verifies the given block's uncles and applies the Ethereum -// consensus rules to the various block headers included; it will return an -// error if any of the included uncle headers were invalid. It returns an error -// if the validation failed. -func (v *BlockValidator) VerifyUncles(block, parent *types.Block) error { - // validate that there are at most 2 uncles included in this block - if len(block.Uncles()) > 2 { - return ValidationError("Block can only contain maximum 2 uncles (contained %v)", len(block.Uncles())) - } - - uncles := set.New() - ancestors := make(map[common.Hash]*types.Block) - for _, ancestor := range v.bc.GetBlocksFromHash(block.ParentHash(), 7) { - ancestors[ancestor.Hash()] = ancestor - // Include ancestors uncles in the uncle set. Uncles must be unique. - for _, uncle := range ancestor.Uncles() { - uncles.Add(uncle.Hash()) - } - } - ancestors[block.Hash()] = block - uncles.Add(block.Hash()) - - for i, uncle := range block.Uncles() { - hash := uncle.Hash() - if uncles.Has(hash) { - // Error not unique - return UncleError("uncle[%d](%x) not unique", i, hash[:4]) - } - uncles.Add(hash) - - if ancestors[hash] != nil { - branch := fmt.Sprintf(" O - %x\n |\n", block.Hash()) - for h := range ancestors { - branch += fmt.Sprintf(" O - %x\n |\n", h) - } - log.Warn(branch) - return UncleError("uncle[%d](%x) is ancestor", i, hash[:4]) - } - - if ancestors[uncle.ParentHash] == nil || uncle.ParentHash == parent.Hash() { - return UncleError("uncle[%d](%x)'s parent is not ancestor (%x)", i, hash[:4], uncle.ParentHash[0:4]) - } - - if err := ValidateHeader(v.config, v.Pow, uncle, ancestors[uncle.ParentHash].Header(), true, true); err != nil { - return ValidationError(fmt.Sprintf("uncle[%d](%x) header invalid: %v", i, hash[:4], err)) - } - } - - return nil -} - -// ValidateHeader validates the given header and, depending on the pow arg, -// checks the proof of work of the given header. Returns an error if the -// validation failed. -func (v *BlockValidator) ValidateHeader(header, parent *types.Header, checkPow bool) error { - // Short circuit if the parent is missing. - if parent == nil { - return ParentError(header.ParentHash) - } - // Short circuit if the header's already known or its parent is missing - if v.bc.HasHeader(header.Hash()) { - return nil - } - return ValidateHeader(v.config, v.Pow, header, parent, checkPow, false) -} - -// Validates a header. Returns an error if the header is invalid. -// -// See YP section 4.3.4. "Block Header Validity" -func ValidateHeader(config *params.ChainConfig, pow pow.PoW, header *types.Header, parent *types.Header, checkPow, uncle bool) error { - if uint64(len(header.Extra)) > params.MaximumExtraDataSize { - return fmt.Errorf("Header extra data too long (%d)", len(header.Extra)) - } - - if uncle { - if header.Time.Cmp(math.MaxBig256) == 1 { - return BlockTSTooBigErr - } - } else { - if header.Time.Cmp(big.NewInt(time.Now().Unix())) == 1 { - return BlockFutureErr - } - } - if header.Time.Cmp(parent.Time) != 1 { - return BlockEqualTSErr - } - - expd := CalcDifficulty(config, header.Time.Uint64(), parent.Time.Uint64(), parent.Number, parent.Difficulty) - if expd.Cmp(header.Difficulty) != 0 { - return fmt.Errorf("Difficulty check failed for header (remote: %v local: %v)", header.Difficulty, expd) - } - - a := new(big.Int).Set(parent.GasLimit) - a = a.Sub(a, header.GasLimit) - a.Abs(a) - b := new(big.Int).Set(parent.GasLimit) - b = b.Div(b, params.GasLimitBoundDivisor) - if !(a.Cmp(b) < 0) || (header.GasLimit.Cmp(params.MinGasLimit) == -1) { - return fmt.Errorf("GasLimit check failed for header (remote: %v local_max: %v)", header.GasLimit, b) - } - - num := new(big.Int).Set(parent.Number) - num.Sub(header.Number, num) - if num.Cmp(big.NewInt(1)) != 0 { - return BlockNumberErr - } - - if checkPow { - // Verify the nonce of the header. Return an error if it's not valid - if err := pow.Verify(types.NewBlockWithHeader(header)); err != nil { - return &BlockNonceErr{header.Number, header.Hash(), header.Nonce.Uint64()} - } - } - // If all checks passed, validate the extra-data field for hard forks - if err := ValidateDAOHeaderExtraData(config, header); err != nil { - return err - } - if !uncle && config.EIP150Block != nil && config.EIP150Block.Cmp(header.Number) == 0 { - if config.EIP150Hash != (common.Hash{}) && config.EIP150Hash != header.Hash() { - return ValidationError("Homestead gas reprice fork hash mismatch: have 0x%x, want 0x%x", header.Hash(), config.EIP150Hash) - } - } - return nil -} - -// CalcDifficulty is the difficulty adjustment algorithm. It returns -// the difficulty that a new block should have when created at time -// given the parent block's time and difficulty. -func CalcDifficulty(config *params.ChainConfig, time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int { - if config.IsHomestead(new(big.Int).Add(parentNumber, common.Big1)) { - return calcDifficultyHomestead(time, parentTime, parentNumber, parentDiff) - } else { - return calcDifficultyFrontier(time, parentTime, parentNumber, parentDiff) - } -} - -func calcDifficultyHomestead(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int { - // https://github.com/ethereum/EIPs/blob/master/EIPS/eip-2.mediawiki - // algorithm: - // diff = (parent_diff + - // (parent_diff / 2048 * max(1 - (block_timestamp - parent_timestamp) // 10, -99)) - // ) + 2^(periodCount - 2) - - bigTime := new(big.Int).SetUint64(time) - bigParentTime := new(big.Int).SetUint64(parentTime) - - // holds intermediate values to make the algo easier to read & audit - x := new(big.Int) - y := new(big.Int) - - // 1 - (block_timestamp -parent_timestamp) // 10 - x.Sub(bigTime, bigParentTime) - x.Div(x, big10) - x.Sub(common.Big1, x) - - // max(1 - (block_timestamp - parent_timestamp) // 10, -99))) - if x.Cmp(bigMinus99) < 0 { - x.Set(bigMinus99) - } - - // (parent_diff + parent_diff // 2048 * max(1 - (block_timestamp - parent_timestamp) // 10, -99)) - y.Div(parentDiff, params.DifficultyBoundDivisor) - x.Mul(y, x) - x.Add(parentDiff, x) - - // minimum difficulty can ever be (before exponential factor) - if x.Cmp(params.MinimumDifficulty) < 0 { - x.Set(params.MinimumDifficulty) - } - - // for the exponential factor - periodCount := new(big.Int).Add(parentNumber, common.Big1) - periodCount.Div(periodCount, ExpDiffPeriod) - - // the exponential factor, commonly referred to as "the bomb" - // diff = diff + 2^(periodCount - 2) - if periodCount.Cmp(common.Big1) > 0 { - y.Sub(periodCount, common.Big2) - y.Exp(common.Big2, y, nil) - x.Add(x, y) - } - - return x -} - -func calcDifficultyFrontier(time, parentTime uint64, parentNumber, parentDiff *big.Int) *big.Int { - diff := new(big.Int) - adjust := new(big.Int).Div(parentDiff, params.DifficultyBoundDivisor) - bigTime := new(big.Int) - bigParentTime := new(big.Int) - - bigTime.SetUint64(time) - bigParentTime.SetUint64(parentTime) - - if bigTime.Sub(bigTime, bigParentTime).Cmp(params.DurationLimit) < 0 { - diff.Add(parentDiff, adjust) - } else { - diff.Sub(parentDiff, adjust) - } - if diff.Cmp(params.MinimumDifficulty) < 0 { - diff.Set(params.MinimumDifficulty) - } - - periodCount := new(big.Int).Add(parentNumber, common.Big1) - periodCount.Div(periodCount, ExpDiffPeriod) - if periodCount.Cmp(common.Big1) > 0 { - // diff = diff + 2^(periodCount - 2) - expDiff := periodCount.Sub(periodCount, common.Big2) - expDiff.Exp(common.Big2, expDiff, nil) - diff.Add(diff, expDiff) - diff = math.BigMax(diff, params.MinimumDifficulty) - } - - return diff -} - // CalcGasLimit computes the gas limit of the next block after parent. // The result may be modified by the caller. // This is miner strategy, not consensus protocol. |