diskimage-builder/diskimage_builder/elements/ramdisk/init.d/30-start-network

echo "starting network $BOOT_MAC_ADDRESS"
t=0
while ! BOOT_INTERFACE=$(find_interface "$BOOT_MAC_ADDRESS"); do
    t=`expr "$t" + 5`
    if [ "$t" -gt 10 ]; then
        break
    fi
    sleep 5
done
if [ -z "$BOOT_INTERFACE" ]; then
    err_msg "Could not find an interface that owns MAC: $BOOT_MAC_ADDRESS"
    troubleshoot
fi

readonly BOOT_INTERFACE

ifconfig lo 127.0.0.1 up
rv=0
ifconfig "$BOOT_INTERFACE" up || rv=1
if [ $rv -ne 0 ]; then
    sleep 10
    rv=0
    ifconfig "$BOOT_INTERFACE" up || rv=1
    if [ $? -ne 0 ]; then
        err_msg "Failed to ifconfig up $BOOT_INTERFACE"
        troubleshoot
    fi
fi

# Check if boot IP address was specific or retrieve from DHCP
if [ -n "$BOOT_IP_ADDRESS" ]; then
    ifconfig "$BOOT_INTERFACE" "$BOOT_IP_ADDRESS" netmask "$BOOT_NETMASK"
    route del default || true
    route add default gw $BOOT_GATEWAY
else
    dhclient -1 "$BOOT_INTERFACE"
    if [[ $? == 2 ]]; then
        echo "Error getting IP address for $BOOT_INTERFACE with MAC \
              $BOOT_MAC_ADDRESS"
        troubleshoot
    fi

    BOOT_IP_ADDRESS=$(ifconfig "$BOOT_INTERFACE" | grep 'inet addr:' | \
                      cut -d: -f2 | awk '{ print $1}')
    BOOT_NETMASK=$(ifconfig "$BOOT_INTERFACE" | grep 'Mask:' | cut -d':' -f4)
    BOOT_GATEWAY=$(route -n | grep "$BOOT_INTERFACE" | grep '^0.0.0.0' | \
                   awk '{print $2}')
    echo "obtained the following from dhcp: "
    echo " ip address = $BOOT_IP_ADDRESS"
    echo " netmask = $BOOT_NETMASK"
    echo " gateway = $BOOT_GATEWAY"
fi