Android VPN prevent out traffic from tun0 -

i have crated vpn client on android device, when tun0 created traffic routed vis tun0. prevent out traffic going via tun0. please let me know there prevent out traffic via tun0.

if exclude apps sending data through vpnservice, there api on builder.

in vpnservice:

builder builder = new builder(); builder.addaddress(tunnel_address, 32); // local address of tun (?) 

to exclude specific apps vpn use:

builder.adddisallowedapplication(packagenameofexcludedapp);