eth, eth/downloader: pass the eth protocol version through

eth/downloader/downloader.go

@@ -175,7 +175,7 @@ func (d *Downloader) Synchronising() bool {
 
 // RegisterPeer injects a new download peer into the set of block source to be
 // used for fetching hashes and blocks from.
-func (d *Downloader) RegisterPeer(id string, head common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) error {
+func (d *Downloader) RegisterPeer(id string, version int, head common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) error {
 	// If the peer wants to send a banned hash, reject
 	if d.banned.Has(head) {
 		glog.V(logger.Debug).Infoln("Register rejected, head hash banned:", id)
@@ -183,7 +183,7 @@ func (d *Downloader) RegisterPeer(id string, head common.Hash, getHashes hashFet
 	}
 	// Otherwise try to construct and register the peer
 	glog.V(logger.Detail).Infoln("Registering peer", id)
-	if err := d.peers.Register(newPeer(id, head, getHashes, getBlocks)); err != nil {
+	if err := d.peers.Register(newPeer(id, version, head, getHashes, getBlocks)); err != nil {
 		glog.V(logger.Error).Infoln("Register failed:", err)
 		return err
 	}

eth/downloader/peer.go

@@ -39,11 +39,13 @@ type peer struct {
 
 	getHashes hashFetcherFn  // Method to retrieve a batch of hashes (mockable for testing)
 	getBlocks blockFetcherFn // Method to retrieve a batch of blocks (mockable for testing)
+
+	version int // Eth protocol version number to switch strategies
 }
 
 // newPeer create a new downloader peer, with specific hash and block retrieval
 // mechanisms.
-func newPeer(id string, head common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) *peer {
+func newPeer(id string, version int, head common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) *peer {
 	return &peer{
 		id:        id,
 		head:      head,
@@ -51,6 +53,7 @@ func newPeer(id string, head common.Hash, getHashes hashFetcherFn, getBlocks blo
 		getHashes: getHashes,
 		getBlocks: getBlocks,
 		ignored:   set.New(),
+		version:   version,
 	}
 }
 

eth/handler.go

@@ -181,7 +181,7 @@ func (pm *ProtocolManager) handle(p *peer) error {
 	defer pm.removePeer(p.id)
 
 	// Register the peer in the downloader. If the downloader considers it banned, we disconnect
-	if err := pm.downloader.RegisterPeer(p.id, p.Head(), p.RequestHashes, p.RequestBlocks); err != nil {
+	if err := pm.downloader.RegisterPeer(p.id, p.version, p.Head(), p.RequestHashes, p.RequestBlocks); err != nil {
 		return err
 	}
 	// Propagate existing transactions. new transactions appearing