Mine

config interface wan
        option ifname   eth0
        option proto    dhcp

config interface loopback
        option ifname   lo
        option proto    static
        option ipaddr   127.0.0.1
        option netmask  255.0.0.0

config interface lan
        option ifname   eth0
        option proto    'dhcp'
        option ipaddr   '192.168.1.100'
        option netmask  '255.255.255.0'
        option gateway  '192.168.0.1'
        option dns      '192.168.0.1'

config wifi-device        'wifi0'
       option type        'atheros'
       option channel     '1'
       option disabled    '0'
       optinterface wan