[release/1.3.4] p2p: EIP-8 changes

Conflicts:
	p2p/rlpx.go

Author: fjl

p2p/message_test.go

@@ -143,7 +143,8 @@ func TestEOFSignal(t *testing.T) {
 }
 
 func unhex(str string) []byte {
-	b, err := hex.DecodeString(strings.Replace(str, "\n", "", -1))
+	r := strings.NewReplacer("\t", "", " ", "", "\n", "")
+	b, err := hex.DecodeString(r.Replace(str))
 	if err != nil {
 		panic(fmt.Sprintf("invalid hex string: %q", str))
 	}

p2p/peer.go

@@ -56,6 +56,9 @@ type protoHandshake struct {
 	Caps       []Cap
 	ListenPort uint64
 	ID         discover.NodeID
+
+	// Ignore additional fields (for forward compatibility).
+	Rest []rlp.RawValue `rlp:"tail"`
 }
 
 // Peer represents a connected remote node.