Improve darwin tun performance

internal/fdbased_darwin/errno.go

@@ -0,0 +1,54 @@
+package fdbased
+
+import (
+	"github.com/sagernet/gvisor/pkg/tcpip"
+
+	"golang.org/x/sys/unix"
+)
+
+func TranslateErrno(e unix.Errno) tcpip.Error {
+	switch e {
+	case unix.EEXIST:
+		return &tcpip.ErrDuplicateAddress{}
+	case unix.ENETUNREACH:
+		return &tcpip.ErrHostUnreachable{}
+	case unix.EINVAL:
+		return &tcpip.ErrInvalidEndpointState{}
+	case unix.EALREADY:
+		return &tcpip.ErrAlreadyConnecting{}
+	case unix.EISCONN:
+		return &tcpip.ErrAlreadyConnected{}
+	case unix.EADDRINUSE:
+		return &tcpip.ErrPortInUse{}
+	case unix.EADDRNOTAVAIL:
+		return &tcpip.ErrBadLocalAddress{}
+	case unix.EPIPE:
+		return &tcpip.ErrClosedForSend{}
+	case unix.EWOULDBLOCK:
+		return &tcpip.ErrWouldBlock{}
+	case unix.ECONNREFUSED:
+		return &tcpip.ErrConnectionRefused{}
+	case unix.ETIMEDOUT:
+		return &tcpip.ErrTimeout{}
+	case unix.EINPROGRESS:
+		return &tcpip.ErrConnectStarted{}
+	case unix.EDESTADDRREQ:
+		return &tcpip.ErrDestinationRequired{}
+	case unix.ENOTSUP:
+		return &tcpip.ErrNotSupported{}
+	case unix.ENOTTY:
+		return &tcpip.ErrQueueSizeNotSupported{}
+	case unix.ENOTCONN:
+		return &tcpip.ErrNotConnected{}
+	case unix.ECONNRESET:
+		return &tcpip.ErrConnectionReset{}
+	case unix.ECONNABORTED:
+		return &tcpip.ErrConnectionAborted{}
+	case unix.EMSGSIZE:
+		return &tcpip.ErrMessageTooLong{}
+	case unix.ENOBUFS:
+		return &tcpip.ErrNoBufferSpace{}
+	default:
+		return &tcpip.ErrInvalidEndpointState{}
+	}
+}