diff options
Diffstat (limited to 'eth/downloader/downloader.go')
| -rw-r--r-- | eth/downloader/downloader.go | 32 |
1 files changed, 22 insertions, 10 deletions
diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go index 4c8b2e8d0..e3e22a784 100644 --- a/eth/downloader/downloader.go +++ b/eth/downloader/downloader.go @@ -21,6 +21,7 @@ import ( "bytes" "errors" "math" + "math/big" "math/rand" "sync" "sync/atomic" @@ -232,10 +233,10 @@ func (d *Downloader) UnregisterPeer(id string) error { // Synchronise tries to sync up our local block chain with a remote peer, both // adding various sanity checks as well as wrapping it with various log entries. -func (d *Downloader) Synchronise(id string, head common.Hash) { - glog.V(logger.Detail).Infof("Attempting synchronisation: %v, 0x%x", id, head) +func (d *Downloader) Synchronise(id string, head common.Hash, td *big.Int) { + glog.V(logger.Detail).Infof("Attempting synchronisation: %v, head 0x%x, TD %v", id, head[:4], td) - switch err := d.synchronise(id, head); err { + switch err := d.synchronise(id, head, td); err { case nil: glog.V(logger.Detail).Infof("Synchronisation completed") @@ -257,7 +258,7 @@ func (d *Downloader) Synchronise(id string, head common.Hash) { // synchronise will select the peer and use it for synchronising. If an empty string is given // it will use the best peer possible and synchronize if it's TD is higher than our own. If any of the // checks fail an error will be returned. This method is synchronous -func (d *Downloader) synchronise(id string, hash common.Hash) error { +func (d *Downloader) synchronise(id string, hash common.Hash, td *big.Int) error { // Mock out the synchonisation if testing if d.synchroniseMock != nil { return d.synchroniseMock(id, hash) @@ -295,7 +296,7 @@ func (d *Downloader) synchronise(id string, hash common.Hash) error { if p == nil { return errUnknownPeer } - return d.syncWithPeer(p, hash) + return d.syncWithPeer(p, hash, td) } // Has checks if the downloader knows about a particular hash, meaning that its @@ -306,7 +307,7 @@ func (d *Downloader) Has(hash common.Hash) bool { // syncWithPeer starts a block synchronization based on the hash chain from the // specified peer and head hash. -func (d *Downloader) syncWithPeer(p *peer, hash common.Hash) (err error) { +func (d *Downloader) syncWithPeer(p *peer, hash common.Hash, td *big.Int) (err error) { d.mux.Post(StartEvent{}) defer func() { // reset on error @@ -335,7 +336,7 @@ func (d *Downloader) syncWithPeer(p *peer, hash common.Hash) (err error) { return err } errc := make(chan error, 2) - go func() { errc <- d.fetchHashes(p, number+1) }() + go func() { errc <- d.fetchHashes(p, td, number+1) }() go func() { errc <- d.fetchBlocks(number + 1) }() // If any fetcher fails, cancel the other @@ -788,7 +789,7 @@ func (d *Downloader) findAncestor(p *peer) (uint64, error) { // fetchHashes keeps retrieving hashes from the requested number, until no more // are returned, potentially throttling on the way. -func (d *Downloader) fetchHashes(p *peer, from uint64) error { +func (d *Downloader) fetchHashes(p *peer, td *big.Int, from uint64) error { glog.V(logger.Debug).Infof("%v: downloading hashes from #%d", p, from) // Create a timeout timer, and the associated hash fetcher @@ -827,8 +828,19 @@ func (d *Downloader) fetchHashes(p *peer, from uint64) error { case d.processCh <- false: case <-d.cancelCh: } - // Error out if no hashes were retrieved at all - if !gotHashes { + // If no hashes were retrieved at all, the peer violated it's TD promise that it had a + // better chain compared to ours. The only exception is if it's promised blocks were + // already imported by other means (e.g. fecher): + // + // R <remote peer>, L <local node>: Both at block 10 + // R: Mine block 11, and propagate it to L + // L: Queue block 11 for import + // L: Notice that R's head and TD increased compared to ours, start sync + // L: Import of block 11 finishes + // L: Sync begins, and finds common ancestor at 11 + // L: Request new hashes up from 11 (R's TD was higher, it must have something) + // R: Nothing to give + if !gotHashes && td.Cmp(d.headBlock().Td) > 0 { return errStallingPeer } return nil |