enhance xnet StackAsync test and add non-linux stubs for Tap and Bridge

internal/tap.go

@@ -1,4 +1,4 @@
-//go:build linux && !baremetal
+//go:build linux && !tinygo
 
 package internal
 

internal/tap_nolinux.go

@@ -0,0 +1,68 @@
+//go:build !linux || tinygo
+
+package internal
+
+import (
+	"errors"
+	"net/netip"
+)
+
+type Tap struct {
+}
+
+func NewTap(name string, ip netip.Prefix) (*Tap, error) {
+	return nil, errors.ErrUnsupported
+}
+
+func (tap *Tap) IPMask() (netip.Prefix, error) {
+	return netip.Prefix{}, errors.ErrUnsupported
+}
+func (tap *Tap) Read(b []byte) (int, error) {
+	return -1, errors.ErrUnsupported
+}
+func (tap *Tap) Write(b []byte) (int, error) {
+	return -1, errors.ErrUnsupported
+}
+func (tap *Tap) Close() error {
+	return errors.ErrUnsupported
+}
+func (tap *Tap) MTU() (int, error) {
+	return -1, errors.ErrUnsupported
+}
+func (tap *Tap) HardwareAddress6() (hw [6]byte, err error) {
+	return hw, errors.ErrUnsupported
+}
+
+type Bridge struct {
+}
+
+func NewBridge(name string) (*Bridge, error) {
+	return nil, errors.ErrUnsupported
+}
+func (br *Bridge) Write(frame []byte) (int, error) {
+	return -1, errors.ErrUnsupported
+}
+func (br *Bridge) Read(frame []byte) (int, error) {
+	return -1, errors.ErrUnsupported
+}
+func (br *Bridge) Close() error {
+	return errors.ErrUnsupported
+}
+func (tap *Bridge) MTU() (int, error) {
+	return -1, errors.ErrUnsupported
+}
+func (tap *Bridge) HardwareAddress6() (hw [6]byte, err error) {
+	return hw, errors.ErrUnsupported
+}
+
+func (br *Bridge) SetHardwareAddress6(hw [6]byte) error {
+	return errors.ErrUnsupported
+}
+
+func (br *Bridge) IPMask() (netip.Prefix, error) {
+	return netip.Prefix{}, errors.ErrUnsupported
+}
+
+func (br *Bridge) Addr() (netip.Addr, error) {
+	return netip.Addr{}, errors.ErrUnsupported
+}