p2p: get rw for running spec

p2p/peer.go

@@ -345,6 +345,17 @@ outer:
 	return result
 }
 
+func (p *Peer) GetRW(name string, version uint) (MsgReadWriter, error) {
+	for _, proto := range p.running {
+		if proto.Name == name && proto.Version == version {
+			var rw MsgReadWriter = proto
+			return rw, nil
+		}
+	}
+
+	return nil, errors.New("not found")
+}
+
 func (p *Peer) startProtocols(writeStart <-chan struct{}, writeErr chan<- error) {
 	p.wg.Add(len(p.running))
 	for _, proto := range p.running {

p2p/protocols/protocol.go

@@ -223,10 +223,15 @@ func NewPeer(p *p2p.Peer, rw p2p.MsgReadWriter, spec *Spec) *Peer {
 }
 
 // ClonePeer constructs a peer object with an arbitrary Spec, based on an existing Peer
+// if Peer doesn't support Spec, it returns nil
 func ClonePeer(p *Peer, spec *Spec) *Peer {
+	rw, err := p.Peer.GetRW(spec.Name, spec.Version)
+	if err != nil {
+		return nil
+	}
 	return &Peer{
 		Peer: p.Peer,
-		rw:   p.rw,
+		rw:   rw,
 		spec: spec,
 	}
 }