fix end-packet #1.

* End-packet payload shall be ZERO-length byte-string.
* 0xff shall be matching 0x9f.

README.md

@@ -124,11 +124,16 @@ the following format:
 **end-packet**
 
 ```text
-    | len | tag1  | 0xff |
+    | len | tag1  | 0x40 | 0xff |
 ```
 
-* If packet denotes a stream-end, payload will be 1-byte 0xff,
-  and not encoded as byte-array.
+* End-packet does not carry any useful payload, it simply signifies a stream
+  close.
+* For that, tag1 opaque-value is required to identify the stream.
+* 0x40 is the single-byte payload for this packet, which says that the
+  payload-data is ZERO bytes.
+* The last 0xff is important since it will match with 0x9f that indicates
+  a stream-start as Indefinite array of items.
 
 **Reading a frame from socket**
 
@@ -148,6 +153,14 @@ That is a total of: 1 + 3 + 1 + 4
 Incidentally these 9 bytes are enough to learn how many more bytes to read
 from the socket to complete the entire packet.
 
+**Regarding Opaque-value**
+
+By design opaque value should be >= 256. These are ephimeral tag values
+that do not carry any meaning other than identifying the stream. Opaque
+values will continuously reused for the life-time of connection. Users
+are expected to give a range of these ephemeral tag-values, and gofast
+will skip [reserved TAGS](https://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml).
+
 Reserved-tags
 -------------
 

go_rx.go

@@ -74,6 +74,9 @@ func (t *Transport) unframepkt(
 
 	ln, m := cborItemLength(pad[n:])
 	n += m
+	if finish { // railing 0xff
+		ln++
+	}
 
 	// read the full packet
 	n = copy(packet, pad[n:])
@@ -98,7 +101,7 @@ func (t *Transport) unframepkt(
 	rxpkt.opaque, payload = readtp(packet[:ln])
 	rxpkt.post, rxpkt.request = post, request
 	rxpkt.start, rxpkt.strmsg, rxpkt.finish = start, stream, finish
-	if rxpkt.finish /*rxpkt.payload[0] == 0xff*/ { // end-of-stream
+	if rxpkt.finish { // end-of-stream
 		return
 	}
 	// tags

go_tx.go

@@ -25,6 +25,7 @@ func (t *Transport) doTx() {
 		// consolidate.
 		for _, arg := range batch {
 			if len(arg.packet) > 0 {
+				//fmt.Println(hexstring(arg.packet))
 				n += copy(tcpwrite_buf[n:], arg.packet)
 				atomic.AddUint64(&t.n_tx, 1)
 			}

tx.go

@@ -57,12 +57,14 @@ func (t *Transport) finish(stream *Stream, out []byte) (n int) {
 	atomic.AddUint64(&t.n_txfin, 1)
 	var scratch [16]byte
 	n = tag2cbor(tagCborPrefix, out)         // prefix
-	out[n] = 0xc8                            // 0xc7 (end stream, 0b110_01000 <tag,8>)
+	out[n] = 0xc8                            // 0xc8 (end stream, 0b110_01000 <tag,8>)
 	n += 1                                   //
 	m := tag2cbor(stream.opaque, scratch[:]) // tag-opaque
-	scratch[m] = 0xff                        // 0xff (payload)
+	scratch[m] = 0x40                        // zero-len byte-string
 	m += 1
 	n += valbytes2cbor(scratch[:m], out[n:]) // packet
+	out[n] = 0xff                            // 0xff CBOR indefinite end.
+	n += 1
 	return n
 }
 

tx_test.go

@@ -132,7 +132,7 @@ func TestFinish(t *testing.T) {
 	transc := newClient("client", addr, "").Handshake() // init client
 	transv := <-serverch
 
-	ref := []byte{217, 217, 247, 200, 68, 217, 1, 12, 255}
+	ref := []byte{217, 217, 247, 200, 68, 217, 1, 12, 64, 255}
 	stream := transc.getlocalstream(false, nil)
 	out := make([]byte, 1024)
 	n := transc.finish(stream, out)