diff --git a/eth/downloader/beaconsync.go b/eth/downloader/beaconsync.go index 31e26f7c9d..45b45763d2 100644 --- a/eth/downloader/beaconsync.go +++ b/eth/downloader/beaconsync.go @@ -263,10 +263,23 @@ func (d *Downloader) findBeaconAncestor() (uint64, error) { // fetchBeaconHeaders feeds skeleton headers to the downloader queue for scheduling // until sync errors or is finished. func (d *Downloader) fetchBeaconHeaders(from uint64) error { - head, _, err := d.skeleton.Bounds() + head, tail, err := d.skeleton.Bounds() if err != nil { return err } + // A part of headers are not in the skeleton space, try to resolve + // them from the local chain. Note the range should be very short + // and it should only happen when there are less than 64 post-merge + // blocks in the network. + var localHeaders []*types.Header + if from < tail.Number.Uint64() { + count := tail.Number.Uint64() - from + if count > uint64(fsMinFullBlocks) { + return fmt.Errorf("invalid origin (%d) of beacon sync (%d)", from, tail.Number) + } + localHeaders = d.readHeaderRange(tail, int(count)) + log.Warn("Retrieved beacon headers from local", "from", from, "count", count) + } for { // Retrieve a batch of headers and feed it to the header processor var ( @@ -275,8 +288,18 @@ func (d *Downloader) fetchBeaconHeaders(from uint64) error { ) for i := 0; i < maxHeadersProcess && from <= head.Number.Uint64(); i++ { header := d.skeleton.Header(from) + + // The header is not found in skeleton space, try to find it in local chain. + if header == nil && from < tail.Number.Uint64() { + dist := tail.Number.Uint64() - from + if len(localHeaders) >= int(dist) { + header = localHeaders[dist-1] + } + } + // The header is still missing, the beacon sync is corrupted and bail out + // the error here. if header == nil { - header = d.lightchain.GetHeaderByNumber(from) + return fmt.Errorf("missing beacon header %d", from) } headers = append(headers, header) hashes = append(hashes, headers[i].Hash()) diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go index 5ff5f32c4e..0e7c48d8b7 100644 --- a/eth/downloader/downloader.go +++ b/eth/downloader/downloader.go @@ -159,9 +159,6 @@ type LightChain interface { // GetHeaderByHash retrieves a header from the local chain. GetHeaderByHash(common.Hash) *types.Header - // GetHeaderByNumber retrieves a block header from the local chain by number. - GetHeaderByNumber(number uint64) *types.Header - // CurrentHeader retrieves the head header from the local chain. CurrentHeader() *types.Header @@ -486,7 +483,15 @@ func (d *Downloader) syncWithPeer(p *peerConnection, hash common.Hash, td, ttd * // Retrieve the pivot header from the skeleton chain segment but // fallback to local chain if it's not found in skeleton space. if pivot = d.skeleton.Header(number); pivot == nil { - pivot = d.lightchain.GetHeaderByNumber(number) + _, oldest, _ := d.skeleton.Bounds() // error is already checked + if number < oldest.Number.Uint64() { + count := int(oldest.Number.Uint64() - number) // it's capped by fsMinFullBlocks + headers := d.readHeaderRange(oldest, count) + if len(headers) == count { + pivot = headers[len(headers)-1] + log.Warn("Retrieved pivot header from local", "number", pivot.Number, "hash", pivot.Hash(), "latest", latest.Number, "oldest", oldest.Number) + } + } } // Print an error log and return directly in case the pivot header // is still not found. It means the skeleton chain is not linked @@ -1772,3 +1777,25 @@ func (d *Downloader) DeliverSnapPacket(peer *snap.Peer, packet snap.Packet) erro return fmt.Errorf("unexpected snap packet type: %T", packet) } } + +// readHeaderRange returns a list of headers, using the given last header as the base, +// and going backwards towards genesis. This method assumes that the caller already has +// placed a reasonable cap on count. +func (d *Downloader) readHeaderRange(last *types.Header, count int) []*types.Header { + var ( + current = last + headers []*types.Header + ) + for { + parent := d.lightchain.GetHeaderByHash(current.ParentHash) + if parent == nil { + break // The chain is not continuous, or the chain is exhausted + } + headers = append(headers, parent) + if len(headers) >= count { + break + } + current = parent + } + return headers +}