plugeth/core/headerchain.go
Martin Holst Swende 40b6ccf383
core,les: headerchain import in batches (#21471)
* core: add test for headerchain inserts

* core, light: write headerchains in batches

* core: change to one callback per batch of inserted headers + review concerns

* core: error-check on batch write

* core: unexport writeHeaders

* core: remove callback parameter in InsertHeaderChain

The semantics of InsertHeaderChain are now much simpler: it is now an
all-or-nothing operation. The new WriteStatus return value allows
callers to check for the canonicality of the insertion. This change
simplifies use of HeaderChain in package les, where the callback was
previously used to post chain events.

* core: skip some hashing when writing headers

* core: less hashing in header validation

* core: fix headerchain flaw regarding blacklisted hashes

Co-authored-by: Felix Lange <fjl@twurst.com>
2020-12-09 11:13:02 +01:00

653 lines
22 KiB
Go

// Copyright 2015 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 (
crand "crypto/rand"
"errors"
"fmt"
"math"
"math/big"
mrand "math/rand"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/consensus"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/params"
lru "github.com/hashicorp/golang-lru"
)
const (
headerCacheLimit = 512
tdCacheLimit = 1024
numberCacheLimit = 2048
)
// HeaderChain implements the basic block header chain logic that is shared by
// core.BlockChain and light.LightChain. It is not usable in itself, only as
// a part of either structure.
//
// HeaderChain is responsible for maintaining the header chain including the
// header query and updating.
//
// The components maintained by headerchain includes: (1) total difficult
// (2) header (3) block hash -> number mapping (4) canonical number -> hash mapping
// and (5) head header flag.
//
// It is not thread safe either, the encapsulating chain structures should do
// the necessary mutex locking/unlocking.
type HeaderChain struct {
config *params.ChainConfig
chainDb ethdb.Database
genesisHeader *types.Header
currentHeader atomic.Value // Current head of the header chain (may be above the block chain!)
currentHeaderHash common.Hash // Hash of the current head of the header chain (prevent recomputing all the time)
headerCache *lru.Cache // Cache for the most recent block headers
tdCache *lru.Cache // Cache for the most recent block total difficulties
numberCache *lru.Cache // Cache for the most recent block numbers
procInterrupt func() bool
rand *mrand.Rand
engine consensus.Engine
}
// NewHeaderChain creates a new HeaderChain structure. ProcInterrupt points
// to the parent's interrupt semaphore.
func NewHeaderChain(chainDb ethdb.Database, config *params.ChainConfig, engine consensus.Engine, procInterrupt func() bool) (*HeaderChain, error) {
headerCache, _ := lru.New(headerCacheLimit)
tdCache, _ := lru.New(tdCacheLimit)
numberCache, _ := lru.New(numberCacheLimit)
// Seed a fast but crypto originating random generator
seed, err := crand.Int(crand.Reader, big.NewInt(math.MaxInt64))
if err != nil {
return nil, err
}
hc := &HeaderChain{
config: config,
chainDb: chainDb,
headerCache: headerCache,
tdCache: tdCache,
numberCache: numberCache,
procInterrupt: procInterrupt,
rand: mrand.New(mrand.NewSource(seed.Int64())),
engine: engine,
}
hc.genesisHeader = hc.GetHeaderByNumber(0)
if hc.genesisHeader == nil {
return nil, ErrNoGenesis
}
hc.currentHeader.Store(hc.genesisHeader)
if head := rawdb.ReadHeadBlockHash(chainDb); head != (common.Hash{}) {
if chead := hc.GetHeaderByHash(head); chead != nil {
hc.currentHeader.Store(chead)
}
}
hc.currentHeaderHash = hc.CurrentHeader().Hash()
headHeaderGauge.Update(hc.CurrentHeader().Number.Int64())
return hc, nil
}
// GetBlockNumber retrieves the block number belonging to the given hash
// from the cache or database
func (hc *HeaderChain) GetBlockNumber(hash common.Hash) *uint64 {
if cached, ok := hc.numberCache.Get(hash); ok {
number := cached.(uint64)
return &number
}
number := rawdb.ReadHeaderNumber(hc.chainDb, hash)
if number != nil {
hc.numberCache.Add(hash, *number)
}
return number
}
type headerWriteResult struct {
status WriteStatus
ignored int
imported int
lastHash common.Hash
lastHeader *types.Header
}
// WriteHeaders writes a chain of headers into the local chain, given that the parents
// are already known. If the total difficulty of the newly inserted chain becomes
// greater than the current known TD, the canonical chain is reorged.
//
// Note: This method is not concurrent-safe with inserting blocks simultaneously
// into the chain, as side effects caused by reorganisations cannot be emulated
// without the real blocks. Hence, writing headers directly should only be done
// in two scenarios: pure-header mode of operation (light clients), or properly
// separated header/block phases (non-archive clients).
func (hc *HeaderChain) writeHeaders(headers []*types.Header) (result *headerWriteResult, err error) {
if len(headers) == 0 {
return &headerWriteResult{}, nil
}
ptd := hc.GetTd(headers[0].ParentHash, headers[0].Number.Uint64()-1)
if ptd == nil {
return &headerWriteResult{}, consensus.ErrUnknownAncestor
}
var (
lastNumber = headers[0].Number.Uint64() - 1 // Last successfully imported number
lastHash = headers[0].ParentHash // Last imported header hash
newTD = new(big.Int).Set(ptd) // Total difficulty of inserted chain
lastHeader *types.Header
inserted []numberHash // Ephemeral lookup of number/hash for the chain
firstInserted = -1 // Index of the first non-ignored header
)
batch := hc.chainDb.NewBatch()
for i, header := range headers {
var hash common.Hash
// The headers have already been validated at this point, so we already
// know that it's a contiguous chain, where
// headers[i].Hash() == headers[i+1].ParentHash
if i < len(headers)-1 {
hash = headers[i+1].ParentHash
} else {
hash = header.Hash()
}
number := header.Number.Uint64()
newTD.Add(newTD, header.Difficulty)
// If the header is already known, skip it, otherwise store
if !hc.HasHeader(hash, number) {
// Irrelevant of the canonical status, write the TD and header to the database.
rawdb.WriteTd(batch, hash, number, newTD)
hc.tdCache.Add(hash, new(big.Int).Set(newTD))
rawdb.WriteHeader(batch, header)
inserted = append(inserted, numberHash{number, hash})
hc.headerCache.Add(hash, header)
hc.numberCache.Add(hash, number)
if firstInserted < 0 {
firstInserted = i
}
}
lastHeader, lastHash, lastNumber = header, hash, number
}
// Skip the slow disk write of all headers if interrupted.
if hc.procInterrupt() {
log.Debug("Premature abort during headers import")
return &headerWriteResult{}, errors.New("aborted")
}
// Commit to disk!
if err := batch.Write(); err != nil {
log.Crit("Failed to write headers", "error", err)
}
batch.Reset()
var (
head = hc.CurrentHeader().Number.Uint64()
localTD = hc.GetTd(hc.currentHeaderHash, head)
status = SideStatTy
)
// If the total difficulty is higher than our known, add it to the canonical chain
// Second clause in the if statement reduces the vulnerability to selfish mining.
// Please refer to http://www.cs.cornell.edu/~ie53/publications/btcProcFC.pdf
reorg := newTD.Cmp(localTD) > 0
if !reorg && newTD.Cmp(localTD) == 0 {
if lastNumber < head {
reorg = true
} else if lastNumber == head {
reorg = mrand.Float64() < 0.5
}
}
// If the parent of the (first) block is already the canon header,
// we don't have to go backwards to delete canon blocks, but
// simply pile them onto the existing chain
chainAlreadyCanon := headers[0].ParentHash == hc.currentHeaderHash
if reorg {
// If the header can be added into canonical chain, adjust the
// header chain markers(canonical indexes and head header flag).
//
// Note all markers should be written atomically.
markerBatch := batch // we can reuse the batch to keep allocs down
if !chainAlreadyCanon {
// Delete any canonical number assignments above the new head
for i := lastNumber + 1; ; i++ {
hash := rawdb.ReadCanonicalHash(hc.chainDb, i)
if hash == (common.Hash{}) {
break
}
rawdb.DeleteCanonicalHash(markerBatch, i)
}
// Overwrite any stale canonical number assignments, going
// backwards from the first header in this import
var (
headHash = headers[0].ParentHash // inserted[0].parent?
headNumber = headers[0].Number.Uint64() - 1 // inserted[0].num-1 ?
headHeader = hc.GetHeader(headHash, headNumber)
)
for rawdb.ReadCanonicalHash(hc.chainDb, headNumber) != headHash {
rawdb.WriteCanonicalHash(markerBatch, headHash, headNumber)
headHash = headHeader.ParentHash
headNumber = headHeader.Number.Uint64() - 1
headHeader = hc.GetHeader(headHash, headNumber)
}
// If some of the older headers were already known, but obtained canon-status
// during this import batch, then we need to write that now
// Further down, we continue writing the staus for the ones that
// were not already known
for i := 0; i < firstInserted; i++ {
hash := headers[i].Hash()
num := headers[i].Number.Uint64()
rawdb.WriteCanonicalHash(markerBatch, hash, num)
rawdb.WriteHeadHeaderHash(markerBatch, hash)
}
}
// Extend the canonical chain with the new headers
for _, hn := range inserted {
rawdb.WriteCanonicalHash(markerBatch, hn.hash, hn.number)
rawdb.WriteHeadHeaderHash(markerBatch, hn.hash)
}
if err := markerBatch.Write(); err != nil {
log.Crit("Failed to write header markers into disk", "err", err)
}
markerBatch.Reset()
// Last step update all in-memory head header markers
hc.currentHeaderHash = lastHash
hc.currentHeader.Store(types.CopyHeader(lastHeader))
headHeaderGauge.Update(lastHeader.Number.Int64())
// Chain status is canonical since this insert was a reorg.
// Note that all inserts which have higher TD than existing are 'reorg'.
status = CanonStatTy
}
if len(inserted) == 0 {
status = NonStatTy
}
return &headerWriteResult{
status: status,
ignored: len(headers) - len(inserted),
imported: len(inserted),
lastHash: lastHash,
lastHeader: lastHeader,
}, nil
}
func (hc *HeaderChain) ValidateHeaderChain(chain []*types.Header, checkFreq int) (int, error) {
// Do a sanity check that the provided chain is actually ordered and linked
for i := 1; i < len(chain); i++ {
parentHash := chain[i-1].Hash()
if chain[i].Number.Uint64() != chain[i-1].Number.Uint64()+1 || chain[i].ParentHash != parentHash {
// Chain broke ancestry, log a message (programming error) and skip insertion
log.Error("Non contiguous header insert", "number", chain[i].Number, "hash", chain[i].Hash(),
"parent", chain[i].ParentHash, "prevnumber", chain[i-1].Number, "prevhash", parentHash)
return 0, fmt.Errorf("non contiguous insert: item %d is #%d [%x…], item %d is #%d [%x…] (parent [%x…])", i-1, chain[i-1].Number,
parentHash.Bytes()[:4], i, chain[i].Number, chain[i].Hash().Bytes()[:4], chain[i].ParentHash[:4])
}
// If the header is a banned one, straight out abort
if BadHashes[parentHash] {
return i - 1, ErrBlacklistedHash
}
// If it's the last header in the cunk, we need to check it too
if i == len(chain)-1 && BadHashes[chain[i].Hash()] {
return i, ErrBlacklistedHash
}
}
// Generate the list of seal verification requests, and start the parallel verifier
seals := make([]bool, len(chain))
if checkFreq != 0 {
// In case of checkFreq == 0 all seals are left false.
for i := 0; i < len(seals)/checkFreq; i++ {
index := i*checkFreq + hc.rand.Intn(checkFreq)
if index >= len(seals) {
index = len(seals) - 1
}
seals[index] = true
}
// Last should always be verified to avoid junk.
seals[len(seals)-1] = true
}
abort, results := hc.engine.VerifyHeaders(hc, chain, seals)
defer close(abort)
// Iterate over the headers and ensure they all check out
for i := range chain {
// If the chain is terminating, stop processing blocks
if hc.procInterrupt() {
log.Debug("Premature abort during headers verification")
return 0, errors.New("aborted")
}
// Otherwise wait for headers checks and ensure they pass
if err := <-results; err != nil {
return i, err
}
}
return 0, nil
}
// InsertHeaderChain inserts the given headers.
//
// The validity of the headers is NOT CHECKED by this method, i.e. they need to be
// validated by ValidateHeaderChain before calling InsertHeaderChain.
//
// This insert is all-or-nothing. If this returns an error, no headers were written,
// otherwise they were all processed successfully.
//
// The returned 'write status' says if the inserted headers are part of the canonical chain
// or a side chain.
func (hc *HeaderChain) InsertHeaderChain(chain []*types.Header, start time.Time) (WriteStatus, error) {
if hc.procInterrupt() {
return 0, errors.New("aborted")
}
res, err := hc.writeHeaders(chain)
// Report some public statistics so the user has a clue what's going on
context := []interface{}{
"count", res.imported,
"elapsed", common.PrettyDuration(time.Since(start)),
}
if err != nil {
context = append(context, "err", err)
}
if last := res.lastHeader; last != nil {
context = append(context, "number", last.Number, "hash", res.lastHash)
if timestamp := time.Unix(int64(last.Time), 0); time.Since(timestamp) > time.Minute {
context = append(context, []interface{}{"age", common.PrettyAge(timestamp)}...)
}
}
if res.ignored > 0 {
context = append(context, []interface{}{"ignored", res.ignored}...)
}
log.Info("Imported new block headers", context...)
return res.status, err
}
// GetBlockHashesFromHash retrieves a number of block hashes starting at a given
// hash, fetching towards the genesis block.
func (hc *HeaderChain) GetBlockHashesFromHash(hash common.Hash, max uint64) []common.Hash {
// Get the origin header from which to fetch
header := hc.GetHeaderByHash(hash)
if header == nil {
return nil
}
// Iterate the headers until enough is collected or the genesis reached
chain := make([]common.Hash, 0, max)
for i := uint64(0); i < max; i++ {
next := header.ParentHash
if header = hc.GetHeader(next, header.Number.Uint64()-1); header == nil {
break
}
chain = append(chain, next)
if header.Number.Sign() == 0 {
break
}
}
return chain
}
// GetAncestor retrieves the Nth ancestor of a given block. It assumes that either the given block or
// a close ancestor of it is canonical. maxNonCanonical points to a downwards counter limiting the
// number of blocks to be individually checked before we reach the canonical chain.
//
// Note: ancestor == 0 returns the same block, 1 returns its parent and so on.
func (hc *HeaderChain) GetAncestor(hash common.Hash, number, ancestor uint64, maxNonCanonical *uint64) (common.Hash, uint64) {
if ancestor > number {
return common.Hash{}, 0
}
if ancestor == 1 {
// in this case it is cheaper to just read the header
if header := hc.GetHeader(hash, number); header != nil {
return header.ParentHash, number - 1
}
return common.Hash{}, 0
}
for ancestor != 0 {
if rawdb.ReadCanonicalHash(hc.chainDb, number) == hash {
ancestorHash := rawdb.ReadCanonicalHash(hc.chainDb, number-ancestor)
if rawdb.ReadCanonicalHash(hc.chainDb, number) == hash {
number -= ancestor
return ancestorHash, number
}
}
if *maxNonCanonical == 0 {
return common.Hash{}, 0
}
*maxNonCanonical--
ancestor--
header := hc.GetHeader(hash, number)
if header == nil {
return common.Hash{}, 0
}
hash = header.ParentHash
number--
}
return hash, number
}
// GetTd retrieves a block's total difficulty in the canonical chain from the
// database by hash and number, caching it if found.
func (hc *HeaderChain) GetTd(hash common.Hash, number uint64) *big.Int {
// Short circuit if the td's already in the cache, retrieve otherwise
if cached, ok := hc.tdCache.Get(hash); ok {
return cached.(*big.Int)
}
td := rawdb.ReadTd(hc.chainDb, hash, number)
if td == nil {
return nil
}
// Cache the found body for next time and return
hc.tdCache.Add(hash, td)
return td
}
// GetTdByHash retrieves a block's total difficulty in the canonical chain from the
// database by hash, caching it if found.
func (hc *HeaderChain) GetTdByHash(hash common.Hash) *big.Int {
number := hc.GetBlockNumber(hash)
if number == nil {
return nil
}
return hc.GetTd(hash, *number)
}
// GetHeader retrieves a block header from the database by hash and number,
// caching it if found.
func (hc *HeaderChain) GetHeader(hash common.Hash, number uint64) *types.Header {
// Short circuit if the header's already in the cache, retrieve otherwise
if header, ok := hc.headerCache.Get(hash); ok {
return header.(*types.Header)
}
header := rawdb.ReadHeader(hc.chainDb, hash, number)
if header == nil {
return nil
}
// Cache the found header for next time and return
hc.headerCache.Add(hash, header)
return header
}
// GetHeaderByHash retrieves a block header from the database by hash, caching it if
// found.
func (hc *HeaderChain) GetHeaderByHash(hash common.Hash) *types.Header {
number := hc.GetBlockNumber(hash)
if number == nil {
return nil
}
return hc.GetHeader(hash, *number)
}
// HasHeader checks if a block header is present in the database or not.
// In theory, if header is present in the database, all relative components
// like td and hash->number should be present too.
func (hc *HeaderChain) HasHeader(hash common.Hash, number uint64) bool {
if hc.numberCache.Contains(hash) || hc.headerCache.Contains(hash) {
return true
}
return rawdb.HasHeader(hc.chainDb, hash, number)
}
// GetHeaderByNumber retrieves a block header from the database by number,
// caching it (associated with its hash) if found.
func (hc *HeaderChain) GetHeaderByNumber(number uint64) *types.Header {
hash := rawdb.ReadCanonicalHash(hc.chainDb, number)
if hash == (common.Hash{}) {
return nil
}
return hc.GetHeader(hash, number)
}
func (hc *HeaderChain) GetCanonicalHash(number uint64) common.Hash {
return rawdb.ReadCanonicalHash(hc.chainDb, number)
}
// CurrentHeader retrieves the current head header of the canonical chain. The
// header is retrieved from the HeaderChain's internal cache.
func (hc *HeaderChain) CurrentHeader() *types.Header {
return hc.currentHeader.Load().(*types.Header)
}
// SetCurrentHeader sets the in-memory head header marker of the canonical chan
// as the given header.
func (hc *HeaderChain) SetCurrentHeader(head *types.Header) {
hc.currentHeader.Store(head)
hc.currentHeaderHash = head.Hash()
headHeaderGauge.Update(head.Number.Int64())
}
type (
// UpdateHeadBlocksCallback is a callback function that is called by SetHead
// before head header is updated. The method will return the actual block it
// updated the head to (missing state) and a flag if setHead should continue
// rewinding till that forcefully (exceeded ancient limits)
UpdateHeadBlocksCallback func(ethdb.KeyValueWriter, *types.Header) (uint64, bool)
// DeleteBlockContentCallback is a callback function that is called by SetHead
// before each header is deleted.
DeleteBlockContentCallback func(ethdb.KeyValueWriter, common.Hash, uint64)
)
// SetHead rewinds the local chain to a new head. Everything above the new head
// will be deleted and the new one set.
func (hc *HeaderChain) SetHead(head uint64, updateFn UpdateHeadBlocksCallback, delFn DeleteBlockContentCallback) {
var (
parentHash common.Hash
batch = hc.chainDb.NewBatch()
origin = true
)
for hdr := hc.CurrentHeader(); hdr != nil && hdr.Number.Uint64() > head; hdr = hc.CurrentHeader() {
num := hdr.Number.Uint64()
// Rewind block chain to new head.
parent := hc.GetHeader(hdr.ParentHash, num-1)
if parent == nil {
parent = hc.genesisHeader
}
parentHash = hdr.ParentHash
// Notably, since geth has the possibility for setting the head to a low
// height which is even lower than ancient head.
// In order to ensure that the head is always no higher than the data in
// the database (ancient store or active store), we need to update head
// first then remove the relative data from the database.
//
// Update head first(head fast block, head full block) before deleting the data.
markerBatch := hc.chainDb.NewBatch()
if updateFn != nil {
newHead, force := updateFn(markerBatch, parent)
if force && newHead < head {
log.Warn("Force rewinding till ancient limit", "head", newHead)
head = newHead
}
}
// Update head header then.
rawdb.WriteHeadHeaderHash(markerBatch, parentHash)
if err := markerBatch.Write(); err != nil {
log.Crit("Failed to update chain markers", "error", err)
}
hc.currentHeader.Store(parent)
hc.currentHeaderHash = parentHash
headHeaderGauge.Update(parent.Number.Int64())
// If this is the first iteration, wipe any leftover data upwards too so
// we don't end up with dangling daps in the database
var nums []uint64
if origin {
for n := num + 1; len(rawdb.ReadAllHashes(hc.chainDb, n)) > 0; n++ {
nums = append([]uint64{n}, nums...) // suboptimal, but we don't really expect this path
}
origin = false
}
nums = append(nums, num)
// Remove the related data from the database on all sidechains
for _, num := range nums {
// Gather all the side fork hashes
hashes := rawdb.ReadAllHashes(hc.chainDb, num)
if len(hashes) == 0 {
// No hashes in the database whatsoever, probably frozen already
hashes = append(hashes, hdr.Hash())
}
for _, hash := range hashes {
if delFn != nil {
delFn(batch, hash, num)
}
rawdb.DeleteHeader(batch, hash, num)
rawdb.DeleteTd(batch, hash, num)
}
rawdb.DeleteCanonicalHash(batch, num)
}
}
// Flush all accumulated deletions.
if err := batch.Write(); err != nil {
log.Crit("Failed to rewind block", "error", err)
}
// Clear out any stale content from the caches
hc.headerCache.Purge()
hc.tdCache.Purge()
hc.numberCache.Purge()
}
// SetGenesis sets a new genesis block header for the chain
func (hc *HeaderChain) SetGenesis(head *types.Header) {
hc.genesisHeader = head
}
// Config retrieves the header chain's chain configuration.
func (hc *HeaderChain) Config() *params.ChainConfig { return hc.config }
// Engine retrieves the header chain's consensus engine.
func (hc *HeaderChain) Engine() consensus.Engine { return hc.engine }
// GetBlock implements consensus.ChainReader, and returns nil for every input as
// a header chain does not have blocks available for retrieval.
func (hc *HeaderChain) GetBlock(hash common.Hash, number uint64) *types.Block {
return nil
}