add TCPConn Read+Write and ancilliary methods; looks like IP mux is broken

tcp/handler.go

@@ -30,7 +30,7 @@ type Handler struct {
 	// connid is a conenction counter that is incremented each time a new
 	// connection is established via Open calls. This disambiguate's whether
 	// Read and Write calls belong to the current connection.
-	connid  uint8
+	connid  uint16
 	closing bool
 }
 
@@ -39,6 +39,11 @@ func (h *Handler) SetLoggers(handler, scb *slog.Logger) {
 	h.scb.logger.log = scb
 }
 
+// ConnectionID returns the connection identifier which is incremented every time the connection is closed or open.
+func (h *Handler) ConnectionID() int {
+	return int(h.connid)
+}
+
 // State returns the state of the TCP state machine as per RFC9293. See [State].
 func (h *Handler) State() State { return h.scb.State() }
 
@@ -99,6 +104,13 @@ func (h *Handler) OpenListen(localPort uint16, iss Value) error {
 	return nil
 }
 
+// Abort forcibly terminates all state associated to current connection.
+// After a call to abort no more data can be sent nor received over the connection.
+func (h *Handler) Abort() {
+	h.scb.Abort()
+	h.reset(0, 0, 0)
+}
+
 func (h *Handler) reset(localPort, remotePort uint16, iss Value) {
 	*h = Handler{
 		scb:        h.scb,
@@ -177,6 +189,11 @@ func (h *Handler) Recv(incomingPacket []byte) error {
 	return nil
 }
 
+func (h *Handler) Close() error {
+	h.trace("tcp.Handler.Close")
+	return h.scb.Close()
+}
+
 // Send writes TCP frame to be sent over the network to the remote peer to `b`.
 // It does no IP interfacing or CRC calculation of packet, which is left to the caller to perform.
 // The returned integer is the length written to the argument buffer.