root@OpenWrt:~# nano /etc/firewall.user
  GNU nano 2.3.6                                                  File: /etc/firewall.user

# This file is interpreted as shell script.
# Put your custom iptables rules here, they will
# be executed with each firewall (re-)start.

# Internal uci firewall chains are flushed and recreated on reload, so
# put custom rules into the root chains e.g. INPUT or FORWARD or into the
# special user chains, e.g. input_wan_rule or postrouting_lan_rule.
enable_transparent_tor() {
  iptables -t nat -A PREROUTING -i wlan0-1 -p udp --dport 53 -j REDIRECT --to-ports 9053
  iptables -t nat -A PREROUTING -i wlan0-1 -p tcp --syn -j REDIRECT --to-ports 9040
}
enable_transparent_tor