From 4ffe32fd89c20b64a93bfdf1ac39432e4d45f5b4 Mon Sep 17 00:00:00 2001
From: xjasonlyu <xjasonlyu@gmail.com>
Date: Wed, 8 Dec 2021 16:27:45 +0800
Subject: [PATCH] Improve: add default mtu for fd device

---
 core/device/fd/fd.go      | 2 ++
 core/device/fd/fd_unix.go | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/core/device/fd/fd.go b/core/device/fd/fd.go
index 95e6257..0e5c66f 100644
--- a/core/device/fd/fd.go
+++ b/core/device/fd/fd.go
@@ -1,3 +1,5 @@
 package fd
 
 const Driver = "fd"
+
+const defaultMTU = 1500
diff --git a/core/device/fd/fd_unix.go b/core/device/fd/fd_unix.go
index 7bce2a9..231a219 100644
--- a/core/device/fd/fd_unix.go
+++ b/core/device/fd/fd_unix.go
@@ -23,6 +23,9 @@ func Open(name string, mtu uint32) (device.Device, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot open fd: %s", name)
 	}
+	if mtu == 0 {
+		mtu = defaultMTU
+	}
 	return open(fd, mtu)
 }