add network feature for relay

internal/util/serial/conn.go

@@ -0,0 +1,72 @@
+package serial
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net"
+	"time"
+)
+
+type conn struct {
+	port   io.ReadWriteCloser
+	laddr  net.Addr
+	raddr  net.Addr
+	cancel context.CancelFunc
+}
+
+func NewConn(port io.ReadWriteCloser, addr net.Addr, cancel context.CancelFunc) net.Conn {
+	return &conn{
+		port:   port,
+		laddr:  addr,
+		raddr:  addr,
+		cancel: cancel,
+	}
+}
+
+func (c *conn) Read(b []byte) (n int, err error) {
+	return c.port.Read(b)
+}
+
+func (c *conn) Write(b []byte) (n int, err error) {
+	return c.port.Write(b)
+}
+
+func (c *conn) LocalAddr() net.Addr {
+	return c.laddr
+}
+
+func (c *conn) RemoteAddr() net.Addr {
+	return c.raddr
+}
+
+func (c *conn) SetDeadline(t time.Time) error {
+	return &net.OpError{Op: "set", Net: "com", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
+}
+
+func (c *conn) SetReadDeadline(t time.Time) error {
+	return &net.OpError{Op: "set", Net: "com", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
+}
+
+func (c *conn) SetWriteDeadline(t time.Time) error {
+	return &net.OpError{Op: "set", Net: "com", Source: nil, Addr: nil, Err: errors.New("deadline not supported")}
+}
+
+func (c *conn) Close() (err error) {
+	if c.cancel != nil {
+		c.cancel()
+	}
+	return c.port.Close()
+}
+
+type Addr struct {
+	Port string
+}
+
+func (a *Addr) Network() string {
+	return "serial"
+}
+
+func (a *Addr) String() string {
+	return a.Port
+}