openwrtv3/target/linux/orion/base-files/etc/uci-defaults/10-network

config_simple() {
cat >> /etc/config/network <<EOF
config interface lan
	option ifname   eth0
	option type     bridge
	option proto    static
	option ipaddr   192.168.1.1
	option netmask  255.255.255.0
	option ip6assign 60
EOF
}

config_dsa() {
cat >> /etc/config/network <<EOF
config interface eth0
	option ifname	eth0

config interface wan
	option ifname	wan
	option proto	dhcp
	option hostname	openwrt

config interface lan
	option ifname   "lan1 lan2 lan3 lan4"
	option type     bridge
	option proto    static
	option ipaddr   192.168.1.1
	option netmask  255.255.255.0
	option ip6assign 60

config interface wan6
	option ifname   wan
	option proto    dhcpv6

config globals globals
	option ula_prefix auto
EOF	
}

cat > /etc/config/network <<EOF
config interface loopback
	option ifname   lo
	option proto    static
	option ipaddr   127.0.0.1
	option netmask  255.0.0.0

EOF

if grep -q lan /proc/net/dev; then
	config_dsa
else
	config_simple
fi