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core, eth: roll back uncertain headers in failed fast syncs

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This commit is contained in:
Péter Szilágyi
2015-10-09 16:21:47 +03:00
parent b97e34a8e4
commit a9d8dfc8e7
6 changed files with 180 additions and 15 deletions
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60
eth/downloader/downloader.go
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@@ -59,8 +59,8 @@ var (
maxQueuedStates = 256 * 1024 // [eth/63] Maximum number of state requests to queue (DOS protection)
maxResultsProcess = 256 // Number of download results to import at once into the chain
headerCheckFrequency = 64 // Verification frequency of the downloaded headers during fast sync
minCheckedHeaders = 1024 // Number of headers to verify fully when approaching the chain head
headerCheckFrequency = 100 // Verification frequency of the downloaded headers during fast sync
minCheckedHeaders = 2048 // Number of headers to verify fully when approaching the chain head
minFullBlocks = 1024 // Number of blocks to retrieve fully even in fast sync
)
@@ -117,6 +117,7 @@ type Downloader struct {
insertHeaders headerChainInsertFn // Injects a batch of headers into the chain
insertBlocks blockChainInsertFn // Injects a batch of blocks into the chain
insertReceipts receiptChainInsertFn // Injects a batch of blocks and their receipts into the chain
rollback chainRollbackFn // Removes a batch of recently added chain links
dropPeer peerDropFn // Drops a peer for misbehaving
// Status
@@ -152,7 +153,7 @@ type Downloader struct {
func New(mode SyncMode, stateDb ethdb.Database, mux *event.TypeMux, hasHeader headerCheckFn, hasBlock blockCheckFn, getHeader headerRetrievalFn,
getBlock blockRetrievalFn, headHeader headHeaderRetrievalFn, headBlock headBlockRetrievalFn, headFastBlock headFastBlockRetrievalFn,
commitHeadBlock headBlockCommitterFn, getTd tdRetrievalFn, insertHeaders headerChainInsertFn, insertBlocks blockChainInsertFn,
insertReceipts receiptChainInsertFn, dropPeer peerDropFn) *Downloader {
insertReceipts receiptChainInsertFn, rollback chainRollbackFn, dropPeer peerDropFn) *Downloader {
return &Downloader{
mode: mode,
@@ -171,6 +172,7 @@ func New(mode SyncMode, stateDb ethdb.Database, mux *event.TypeMux, hasHeader he
insertHeaders: insertHeaders,
insertBlocks: insertBlocks,
insertReceipts: insertReceipts,
rollback: rollback,
dropPeer: dropPeer,
newPeerCh: make(chan *peer, 1),
hashCh: make(chan dataPack, 1),
@@ -383,7 +385,7 @@ func (d *Downloader) syncWithPeer(p *peer, hash common.Hash, td *big.Int) (err e
d.syncStatsChainHeight = latest
d.syncStatsLock.Unlock()
// Initiate the sync using a concurrent header and content retrieval algorithm
// Initiate the sync using a concurrent header and content retrieval algorithm
pivot := uint64(0)
if latest > uint64(minFullBlocks) {
pivot = latest - uint64(minFullBlocks)
@@ -394,10 +396,10 @@ func (d *Downloader) syncWithPeer(p *peer, hash common.Hash, td *big.Int) (err e
d.syncInitHook(origin, latest)
}
errc := make(chan error, 4)
go func() { errc <- d.fetchHeaders(p, td, origin+1) }() // Headers are always retrieved
go func() { errc <- d.fetchBodies(origin + 1) }() // Bodies are retrieved during normal and fast sync
go func() { errc <- d.fetchReceipts(origin + 1) }() // Receipts are retrieved during fast sync
go func() { errc <- d.fetchNodeData() }() // Node state data is retrieved during fast sync
go func() { errc <- d.fetchHeaders(p, td, origin+1, latest) }() // Headers are always retrieved
go func() { errc <- d.fetchBodies(origin + 1) }() // Bodies are retrieved during normal and fast sync
go func() { errc <- d.fetchReceipts(origin + 1) }() // Receipts are retrieved during fast sync
go func() { errc <- d.fetchNodeData() }() // Node state data is retrieved during fast sync
// If any fetcher fails, cancel the others
var fail error
@@ -1049,10 +1051,28 @@ func (d *Downloader) findAncestor(p *peer) (uint64, error) {
//
// The queue parameter can be used to switch between queuing headers for block
// body download too, or directly import as pure header chains.
func (d *Downloader) fetchHeaders(p *peer, td *big.Int, from uint64) error {
func (d *Downloader) fetchHeaders(p *peer, td *big.Int, from, latest uint64) error {
glog.V(logger.Debug).Infof("%v: downloading headers from #%d", p, from)
defer glog.V(logger.Debug).Infof("%v: header download terminated", p)
// Keep a count of uncertain headers to roll back
rollback := []*types.Header{}
defer func() {
if len(rollback) > 0 {
hashes := make([]common.Hash, len(rollback))
for i, header := range rollback {
hashes[i] = header.Hash()
}
d.rollback(hashes)
}
}()
// Calculate the pivoting point for switching from fast to slow sync
pivot := uint64(0)
if d.mode == FastSync && latest > uint64(minFullBlocks) {
pivot = latest - uint64(minFullBlocks)
} else if d.mode == LightSync {
pivot = latest
}
// Create a timeout timer, and the associated hash fetcher
request := time.Now() // time of the last fetch request
timeout := time.NewTimer(0) // timer to dump a non-responsive active peer
@@ -1124,10 +1144,30 @@ func (d *Downloader) fetchHeaders(p *peer, td *big.Int, from uint64) error {
glog.V(logger.Detail).Infof("%v: schedule %d headers from #%d", p, len(headers), from)
if d.mode == FastSync || d.mode == LightSync {
if n, err := d.insertHeaders(headers, headerCheckFrequency); err != nil {
// Collect the yet unknown headers to mark them as uncertain
unknown := make([]*types.Header, 0, len(headers))
for _, header := range headers {
if !d.hasHeader(header.Hash()) {
unknown = append(unknown, header)
}
}
// If we're importing pure headers, verify based on their recentness
frequency := headerCheckFrequency
if headers[len(headers)-1].Number.Uint64()+uint64(minCheckedHeaders) > pivot {
frequency = 1
}
if n, err := d.insertHeaders(headers, frequency); err != nil {
glog.V(logger.Debug).Infof("%v: invalid header #%d [%x…]: %v", p, headers[n].Number, headers[n].Hash().Bytes()[:4], err)
return errInvalidChain
}
// All verifications passed, store newly found uncertain headers
rollback = append(rollback, unknown...)
if len(rollback) > minCheckedHeaders {
rollback = append(rollback[:0], rollback[len(rollback)-minCheckedHeaders:]...)
}
if headers[len(headers)-1].Number.Uint64() >= pivot {
rollback = rollback[:0]
}
}
if d.mode == FullSync || d.mode == FastSync {
inserts := d.queue.Schedule(headers, from)