How can I redirect all traffic to sslocal in tun mode like def1 redirect in OpenVpn?

[GrigoriyPeters]

Hello.
How can I redirect all traffic to sslocal in tun mode like def1 redirect in OpenVpn?
In a nutshell, I'm trying to do the same thing that I do in VPN mode in the Shadowsocks android app.

I've created a tun device:

sudo ip tuntap add mode tun tun0
sudo ifconfig tun0 inet 10.0.0.1 netmask 255.255.255.0 up

And ran sslocal:

sudo sslocal --protocol tun -s "ip:8388" -m "2022-blake3-aes-256-gcm" -k "password" --outbound-bind-interface lo0 --tun-interface-name tun0

And I even get suspiciously good ping via this interface:

ping -I tun0 8.8.8.8
PING 8.8.8.8 (8.8.8.8) from 10.255.0.1 tun0: 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=64 time=0.057 ms

Then I tried to redirect default via IP route:

sudo ip route  add default via 10.255.0.1

But this caused sslocal to start printing errors:

2023-09-27T20:46:28.324713165+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.324753585+07:00 ERROR TCP tunnel failure, 10.255.0.1:46072 <-> 149.154.167.41:80, error: No such device (os error 19)
2023-09-27T20:46:28.324844436+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.324888096+07:00 ERROR TCP tunnel failure, 10.255.0.1:38420 <-> 149.154.167.51:80, error: No such device (os error 19)
2023-09-27T20:46:28.327671775+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.327713285+07:00 ERROR TCP tunnel failure, 10.255.0.1:48760 <-> 149.154.167.41:443, error: No such device (os error 19)
2023-09-27T20:46:28.327794466+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.327831817+07:00 ERROR TCP tunnel failure, 10.255.0.1:41542 <-> 149.154.167.51:443, error: No such device (os error 19)
2023-09-27T20:46:28.328007988+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.328053049+07:00 ERROR TCP tunnel failure, 10.255.0.1:46084 <-> 149.154.167.41:80, error: No such device (os error 19)
2023-09-27T20:46:28.328134650+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.328175760+07:00 ERROR TCP tunnel failure, 10.255.0.1:38426 <-> 149.154.167.51:80, error: No such device (os error 19)
2023-09-27T20:46:28.328260891+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.328304091+07:00 ERROR TCP tunnel failure, 10.255.0.1:46088 <-> 149.154.167.41:80, error: No such device (os error 19)
2023-09-27T20:46:28.673186788+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.673235189+07:00 ERROR TCP tunnel failure, 10.255.0.1:49398 <-> 93.186.225.198:443, error: No such device (os error 19)
2023-09-27T20:46:28.676228950+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.676268061+07:00 ERROR TCP tunnel failure, 10.255.0.1:39950 <-> 34.107.221.82:80, error: No such device (os error 19)
2023-09-27T20:46:28.677389472+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:28.677434163+07:00 ERROR TCP tunnel failure, 10.255.0.1:39952 <-> 34.107.221.82:80, error: No such device (os error 19)
2023-09-27T20:46:29.304753326+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:29.304799596+07:00 ERROR TCP tunnel failure, 10.255.0.1:48770 <-> 149.154.167.41:443, error: No such device (os error 19)
2023-09-27T20:46:29.304857667+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:29.304918958+07:00 ERROR TCP tunnel failure, 10.255.0.1:41546 <-> 149.154.167.51:443, error: No such device (os error 19)
2023-09-27T20:46:29.305237371+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:29.305308372+07:00 ERROR TCP tunnel failure, 10.255.0.1:46100 <-> 149.154.167.41:80, error: No such device (os error 19)
2023-09-27T20:46:29.305418793+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:29.305463533+07:00 ERROR TCP tunnel failure, 10.255.0.1:38430 <-> 149.154.167.51:80, error: No such device (os error 19)
2023-09-27T20:46:29.305728526+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:29.305765806+07:00 ERROR TCP tunnel failure, 10.255.0.1:38444 <-> 149.154.167.51:80, error: No such device (os error 19)
2023-09-27T20:46:29.963219246+07:00 ERROR set SO_BINDTODEVICE error: No such device (os error 19)
2023-09-27T20:46:29.963264947+07:00 ERROR TCP tunnel failure, 10.255.0.1:39962 <-> 34.107.221.82:80, error: No such device (os error 19)

And naturally, the browser can't reach any site.

What I am doing wrong?

Thanks in advance!