naison@naison-virtual-machine:~$ sudo ip route add 10.10.0.0/16 dev tun0
[sudo] password for naison: 
naison@naison-virtual-machine:~$ sudo ip route add 10.10.0.0/16 dev tun0
RTNETLINK answers: File exists
naison@naison-virtual-machine:~$ 

2021/08/21 11:19:21 tuntap_linux.go:40: [tun] ip link set dev tun0 mtu 1350
2021/08/21 11:19:21 tuntap_linux.go:47: [tun] ip address add 223.254.254.2/24 dev tun0
2021/08/21 11:19:21 tuntap_linux.go:54: [tun] ip link set dev tun0 up
2021/08/21 11:19:21 tuntap_linux.go:151: [tun] ip route add 10.10.0.0/16 dev tun0
2021/08/21 11:19:21 main.go:88: ip route add 10.10.0.0/16 dev tun0: file exists