more effort into understanding why TAP interface is so slow on my linux machine to no avail

internet/portstack.go

@@ -0,0 +1,14 @@
+package internet
+
+import "github.com/soypat/lneto"
+
+type PortStack struct {
+	handlers []porthandler
+	proto    lneto.IPProto
+}
+
+type porthandler struct {
+	recv   func([]byte, int) error
+	handle func([]byte, int) (int, error)
+	port   uint16
+}