begin testing tcp listener (not working)

tcp/handler.go

@@ -144,7 +144,7 @@ func (h *Handler) Recv(incomingPacket []byte) error {
 		return err
 	}
 	tfrm.ValidateExceptCRC(&h.validator)
-	err = h.validator.Err()
+	err = h.validator.ErrPop()
 	if err != nil {
 		return err
 	}

tcp/tcp_test.go

@@ -596,8 +596,8 @@ func parseSegment(t *testing.T, b []byte) (tcp.Segment, []byte) {
 		t.Fatalf("not IPv4")
 	}
 	efrm.ValidateSize(&vld)
-	if err := vld.Err(); err != nil {
-		t.Fatal(vld.Err())
+	if err := vld.ErrPop(); err != nil {
+		t.Fatal(vld.ErrPop())
 	}
 	ifrm, err := ipv4.NewFrame(efrm.Payload())
 	if err != nil {
@@ -611,8 +611,8 @@ func parseSegment(t *testing.T, b []byte) (tcp.Segment, []byte) {
 		t.Fatal("invalid IP version", v)
 	}
 	ifrm.ValidateSize(&vld)
-	if err := vld.Err(); err != nil {
-		t.Fatal(vld.Err())
+	if err := vld.ErrPop(); err != nil {
+		t.Fatal(vld.ErrPop())
 	}
 
 	ipl := ifrm.Payload()
@@ -621,7 +621,7 @@ func parseSegment(t *testing.T, b []byte) (tcp.Segment, []byte) {
 		t.Fatal(err)
 	}
 	tfrm.ValidateSize(&vld)
-	if err := vld.Err(); err != nil {
+	if err := vld.ErrPop(); err != nil {
 		t.Fatal(err)
 	}
 	_ = tfrm.String()

tcp/txqueue.go

@@ -50,6 +50,7 @@ type ringidx struct {
 // Reset resets the RingTx's internal state to use buf as the main ring buffer and creates or reuses
 // the packet ring buffer.
 func (rtx *ringTx) Reset(buf []byte, maxqueuedPackets int, seq Value) error {
+	buf = buf[:len(buf):len(buf)] // safely omit capacity section.
 	if maxqueuedPackets <= 0 {
 		return errors.New("queued packets <=0")
 	} else if len(buf) < minBufferSize || len(buf) < maxqueuedPackets {