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-rw-r--r--core/block_validator.go243
1 files changed, 243 insertions, 0 deletions
diff --git a/core/block_validator.go b/core/block_validator.go
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+++ b/core/block_validator.go
@@ -0,0 +1,243 @@
+// Copyright 2014 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package core
+
+import (
+ "fmt"
+ "math/big"
+ "time"
+
+ "github.com/ethereum/go-ethereum/common"
+ "github.com/ethereum/go-ethereum/core/state"
+ "github.com/ethereum/go-ethereum/core/types"
+ "github.com/ethereum/go-ethereum/logger/glog"
+ "github.com/ethereum/go-ethereum/params"
+ "github.com/ethereum/go-ethereum/pow"
+ "gopkg.in/fatih/set.v0"
+)
+
+// BlockValidator is responsible for validating block headers, uncles and
+// processed state.
+//
+// BlockValidator implements Validator.
+type BlockValidator struct {
+ bc *BlockChain // Canonical block chain
+ Pow pow.PoW // Proof of work used for validating
+}
+
+// NewBlockValidator returns a new block validator which is safe for re-use
+func NewBlockValidator(blockchain *BlockChain, pow pow.PoW) *BlockValidator {
+ validator := &BlockValidator{
+ Pow: pow,
+ 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
+// seperately so we can process them in paralel.
+//
+// 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 form accepting
+// false positives where a header is present but the state is not.
+func (v *BlockValidator) ValidateBlock(block *types.Block) error {
+ if v.bc.HasBlock(block.Hash()) {
+ if _, err := state.New(block.Root(), v.bc.chainDb); err == nil {
+ return &KnownBlockError{block.Number(), block.Hash()}
+ }
+ }
+ parent := v.bc.GetBlock(block.ParentHash())
+ if parent == nil {
+ return ParentError(block.ParentHash())
+ }
+ if _, err := state.New(parent.Root(), v.bc.chainDb); err != nil {
+ return ParentError(block.ParentHash())
+ }
+
+ header := block.Header()
+ // validate the block header
+ if err := ValidateHeader(v.Pow, header, parent.Header(), false, false); err != nil {
+ return err
+ }
+ // verify the uncles are correctly rewarded
+ if err := v.VerifyUncles(block, parent); err != nil {
+ return err
+ }
+
+ // Verify UncleHash before running other uncle validations
+ unclesSha := types.CalcUncleHash(block.Uncles())
+ if unclesSha != header.UncleHash {
+ return fmt.Errorf("invalid uncles root hash. received=%x calculated=%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. received=%x calculated=%x", header.TxHash, txSha)
+ }
+
+ return nil
+}
+
+// ValidateState validates the various changes that happen after a state
+// transition, such as amount of used gas, the receipt roots and the state root
+// itself. ValidateState returns a database batch if the validation was a succes
+// otherwise nil and an error is returned.
+func (v *BlockValidator) ValidateState(block, parent *types.Block, statedb *state.StateDB, receipts types.Receipts, usedGas *big.Int) (err error) {
+ header := block.Header()
+ if block.GasUsed().Cmp(usedGas) != 0 {
+ return ValidationError(fmt.Sprintf("gas used error (%v / %v)", block.GasUsed(), usedGas))
+ }
+ // Validate the received block's bloom with the one derived from the generated receipts.
+ // For valid blocks this should always validate to true.
+ rbloom := types.CreateBloom(receipts)
+ if rbloom != header.Bloom {
+ return fmt.Errorf("unable to replicate block's bloom=%x", rbloom)
+ }
+ // Tre receipt Trie's root (R = (Tr [[H1, R1], ... [Hn, R1]]))
+ receiptSha := types.DeriveSha(receipts)
+ if receiptSha != header.ReceiptHash {
+ return fmt.Errorf("invalid receipt root hash. received=%x calculated=%x", header.ReceiptHash, receiptSha)
+ }
+ // Validate the state root against the received state root and throw
+ // an error if they don't match.
+ if root := statedb.IntermediateRoot(); header.Root != root {
+ return fmt.Errorf("invalid merkle root: header=%x computed=%x", header.Root, root)
+ }
+ 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 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)
+ }
+ glog.Infoln(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.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 missing
+ if v.bc.HasHeader(header.Hash()) {
+ return nil
+ }
+ return ValidateHeader(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(pow pow.PoW, header *types.Header, parent *types.Header, checkPow, uncle bool) error {
+ if big.NewInt(int64(len(header.Extra))).Cmp(params.MaximumExtraDataSize) == 1 {
+ return fmt.Errorf("Header extra data too long (%d)", len(header.Extra))
+ }
+
+ if uncle {
+ if header.Time.Cmp(common.MaxBig) == 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(header.Time.Uint64(), parent.Time.Uint64(), parent.Number, parent.Difficulty)
+ if expd.Cmp(header.Difficulty) != 0 {
+ return fmt.Errorf("Difficulty check failed for header %v, %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 %v (%v > %v)", header.GasLimit, a, 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 !pow.Verify(types.NewBlockWithHeader(header)) {
+ return &BlockNonceErr{header.Number, header.Hash(), header.Nonce.Uint64()}
+ }
+ }
+ return nil
+}