[Bug] inappropriate ioctl for device

Verify steps

[X] 如果你可以自己 debug 并解决的话，提交 PR 吧 Is this something you can debug and fix? Send a pull request! Bug fixes and documentation fixes are welcome.
[X] 我已经在 Issue Tracker 中找过我要提出的问题 I have searched on the issue tracker for a related issue.
[X] 我已经使用 dev 分支版本测试过，问题依旧存在 I have tested using the dev branch, and the issue still exists.
[X] 我已经仔细看过 Documentation 并无法自行解决问题 I have read the documentation and was unable to solve the issue.
[X] 这是 Clash 核心的问题，并非我所使用的 Clash 衍生版本（如 OpenClash、KoolClash 等）的特定问题 This is an issue of the Clash core per se, not to the derivatives of Clash, like OpenClash or KoolClash.

Clash version

release最新版(20210310)

What OS are you seeing the problem on?

Linux

Clash config

clash@debian:~$ cat config.yaml
mixed-port: 1080
allow-lan: true
external-controller: 127.0.0.1:9090
secret: ''
tun:
  enable: true
  device-url: dev://ctun
  device-url: fd://5
  dns-listen: 0.0.0.0:53
dns:
  enable: true
  listen: 0.0.0.0:53
  default-nameserver:
    - 114.114.114.114
    - 8.8.8.8
  enhanced-mode: fake-ip
  fake-ip-range: 198.18.0.1/16

  fake-ip-filter:
    - '*.lan'
    - localhost.ptlogin2.qq.com

  nameserver:
    - 114.114.114.114
    - 8.8.8.8
    - tls://dns.rubyfish.cn:853
    - https://1.1.1.1/dns-query

  fallback:
    - tcp://1.1.1.1
proxies:
...
proxy-groups:
...
rules:
- GEOIP,CN,DIRECT
- MATCH,Proxy

Clash log

clash@debian:~$ ./clash-linux-amd64 -d .
INFO[0000] Start initial compatible provider Proxy
ERRO[0000] Start Tun interface error: can't open tun: inappropriate ioctl for device
INFO[0000] Mixed(http+socks5) proxy listening at: :1080
INFO[0000] RESTful API listening at: 127.0.0.1:9090

Description

我对着教程敲命令，启动clash时提示标题里的报错(运行的用户也是clash)，可以麻烦帮我看看是哪一部出问题了吗？我的输入顺序如下

ip tuntap add mode tun user clash name ctun ifconfig ctun up route add -net 198.18.0.0/16 dev ctun

ipconfig运行结果如下

root@debian:~# ifconfig
ctun: flags=4241<UP,POINTOPOINT,NOARP,MULTICAST>  mtu 1500
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 500  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.2.131  netmask 255.255.255.0  broadcast 192.168.2.255
        inet6 fe80::20c:29ff:fe3f:b2ca  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:3f:b2:ca  txqueuelen 1000  (Ethernet)
        RX packets 32177  bytes 44616187 (42.5 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 8313  bytes 608868 (594.5 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

路由表

root@debian:~# route
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.2.2     0.0.0.0         UG    0      0        0 ens33
192.168.2.0     0.0.0.0         255.255.255.0   U     0      0        0 ens33
198.18.0.0      0.0.0.0         255.255.0.0     U     0      0        0 ctun

comzyh / clash

[Bug] inappropriate ioctl for device #14