I wanna stick with Gl.
Found better solution.
uci add_list dhcp.@dnsmasq[0].address='/ru/0.0.0.0'
uci commit dhcp
uci add_list dhcp.@dnsmasq[0].address='/su/0.0.0.0'
uci commit dhcp
service dnsmasq restart
Also you can set adblocking even on weak devices like:
uci add_list dhcp.@dnsmasq[0].addnhosts="/sda1/hosts.txt"
uci commit dhcp
/etc/init.d/dnsmasq restart
This will add hosts file on your SD as additional hosts