add proto version to dht

dht/message.go

@@ -41,6 +41,7 @@ const (
 	headerArgsField      = "4"
 	contactsField        = "contacts"
 	tokenField           = "token"
+	protocolVersionField = "protocolVersion"
 )
 
 // Message is an extension of the bencode marshalling interface for serialized message passing.
@@ -83,11 +84,12 @@ func newMessageID() messageID {
 
 // Request represents the structured request from one node to another.
 type Request struct {
-	ID        messageID
-	NodeID    bits.Bitmap
-	Method    string
-	Arg       *bits.Bitmap
-	StoreArgs *storeArgs
+	ID              messageID
+	NodeID          bits.Bitmap
+	Method          string
+	Arg             *bits.Bitmap
+	StoreArgs       *storeArgs
+	ProtocolVersion int
 }
 
 // MarshalBencode returns the serialized byte slice representation of the request
@@ -133,17 +135,47 @@ func (r *Request) UnmarshalBencode(b []byte) error {
 			return errors.Prefix("request unmarshal", err)
 		}
 	} else if len(raw.Args) > 2 { // 2 because an empty list is `le`
-		tmp := []bits.Bitmap{}
-		err = bencode.DecodeBytes(raw.Args, &tmp)
+		r.Arg, r.ProtocolVersion, err = processArgsAndProtoVersion(raw.Args)
 		if err != nil {
 			return errors.Prefix("request unmarshal", err)
 		}
-		r.Arg = &tmp[0]
 	}
 
 	return nil
 }
 
+func processArgsAndProtoVersion(raw bencode.RawMessage) (arg *bits.Bitmap, version int, err error) {
+	var args []bencode.RawMessage
+	err = bencode.DecodeBytes(raw, &args)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	if len(args) == 0 {
+		return nil, 0, nil
+	}
+
+	var extras map[string]int
+	err = bencode.DecodeBytes(args[len(args)-1], &extras)
+	if err == nil {
+		if v, exists := extras[protocolVersionField]; exists {
+			version = v
+			args = args[:len(args)-1]
+		}
+	}
+
+	if len(args) > 0 {
+		var b bits.Bitmap
+		err = bencode.DecodeBytes(args[0], &b)
+		if err != nil {
+			return nil, 0, err
+		}
+		arg = &b
+	}
+
+	return arg, version, nil
+}
+
 func (r Request) argsDebug() string {
 	if r.StoreArgs != nil {
 		return r.StoreArgs.BlobHash.HexShort() + ", " + r.StoreArgs.Value.LbryID.HexShort() + ":" + strconv.Itoa(r.StoreArgs.Value.Port)
@@ -231,12 +263,13 @@ func (s *storeArgs) UnmarshalBencode(b []byte) error {
 
 // Response represents the structured response one node returns to another.
 type Response struct {
-	ID           messageID
-	NodeID       bits.Bitmap
-	Data         string
-	Contacts     []Contact
-	FindValueKey string
-	Token        string
+	ID              messageID
+	NodeID          bits.Bitmap
+	Data            string
+	Contacts        []Contact
+	FindValueKey    string
+	Token           string
+	ProtocolVersion int
 }
 
 func (r Response) argsDebug() string {
@@ -251,7 +284,7 @@ func (r Response) argsDebug() string {
 
 	str += "|"
 	for _, c := range r.Contacts {
-		str += c.Addr().String() + ":" + c.ID.HexShort() + ","
+		str += c.String() + ","
 	}
 	str = strings.TrimRight(str, ",") + "|"
 
@@ -344,7 +377,15 @@ func (r *Response) UnmarshalBencode(b []byte) error {
 		if err != nil {
 			return err
 		}
-		delete(rawData, tokenField) // it doesnt mess up findValue key finding below
+		delete(rawData, tokenField) // so it doesnt mess up findValue key finding below
+	}
+
+	if protocolVersion, ok := rawData[protocolVersionField]; ok {
+		err = bencode.DecodeBytes(protocolVersion, &r.ProtocolVersion)
+		if err != nil {
+			return err
+		}
+		delete(rawData, protocolVersionField) // so it doesnt mess up findValue key finding below
 	}
 
 	if contacts, ok := rawData[contactsField]; ok {

dht/message_test.go

@@ -167,6 +167,40 @@ func TestDecodeFindNodeResponseWithNoNodes(t *testing.T) {
 	}
 }
 
+func TestDecodeRequestWithProtocolVersion(t *testing.T) {
+	raw, err := hex.DecodeString("6469306569306569316532303a65e1b9afce87c44abc40b4bb466890d2797f0dd269326534383a1baf3dbba8746c7a739f35465e268ace823622c5e8ec1dd7d5d27af5795cfbc54f22a32fbd05d420f241266b3dd16831693365343a70696e676934656c6431353a70726f746f636f6c56657273696f6e693165656565")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	req := Request{}
+	err = bencode.DecodeBytes(raw, &req)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if req.ProtocolVersion != 1 {
+		t.Error("protocol version was not detected correctly")
+	}
+}
+
+func TestDecodeResponseWithProtocolVersion(t *testing.T) {
+	raw, err := hex.DecodeString("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")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	res := Response{}
+	err = bencode.DecodeBytes(raw, &res)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if res.ProtocolVersion != 1 {
+		t.Error("protocol version was not detected correctly")
+	}
+}
+
 func compareResponses(t *testing.T, res, res2 Response) {
 	if res.ID != res2.ID {
 		t.Errorf("expected ID %s, got %s", res.ID, res2.ID)