Improve error processing

gvisor_err.go

@@ -0,0 +1,69 @@
+package tun
+
+import (
+	"net"
+
+	"gvisor.dev/gvisor/pkg/tcpip"
+	"gvisor.dev/gvisor/pkg/tcpip/adapters/gonet"
+)
+
+type gTCPConn struct {
+	*gonet.TCPConn
+}
+
+func (c *gTCPConn) Upstream() any {
+	return c.TCPConn
+}
+
+func (c *gTCPConn) Write(b []byte) (n int, err error) {
+	n, err = c.TCPConn.Write(b)
+	if err == nil {
+		return
+	}
+	err = wrapError(err)
+	return
+}
+
+type gUDPConn struct {
+	*gonet.UDPConn
+}
+
+func (c *gUDPConn) Read(b []byte) (n int, err error) {
+	n, err = c.UDPConn.Read(b)
+	if err == nil {
+		return
+	}
+	err = wrapError(err)
+	return
+}
+
+func (c *gUDPConn) Write(b []byte) (n int, err error) {
+	n, err = c.UDPConn.Write(b)
+	if err == nil {
+		return
+	}
+	err = wrapError(err)
+	return
+}
+
+func wrapStackError(err tcpip.Error) error {
+	switch err.(type) {
+	case *tcpip.ErrClosedForSend:
+		return net.ErrClosed
+	case *tcpip.ErrClosedForReceive:
+		return net.ErrClosed
+	}
+	return wrapStackError(err)
+}
+
+func wrapError(err error) error {
+	if opErr, isOpErr := err.(*net.OpError); isOpErr {
+		switch opErr.Err.Error() {
+		case "endpoint is closed for send":
+			return net.ErrClosed
+		case "endpoint is closed for receive":
+			return net.ErrClosed
+		}
+	}
+	return err
+}