how to bring network up at boot time in linux
 

Hi,

I am working on an embedded linux system, my aim is to activate ethernet interface at boot time. I am using u-boot as bootloader. I passed ip=169.254.1.1:::255.255.255.0:Eddy:eth0:off and eth=00:05:F4:11:22:33 u-boot environment variables to the linux kernel as bootargs and configured linux kernel as IP:kernel level autoconfiguration , enabled. However, that didn't bring the network interface up, as "ifconfig eth0 up" do.

So, I am wondering if it is possible to instruct linux kernel to configure and activate eth0 interface without resorting to user space scripts (ifup and ifconfig)?

Are you considering init scripts as "user space" scripts? These are run at boot time and generally what are used to start up networking by default. (e.g. /etc/init.d/network on RedHat derived distros is linked to /etc/rc?.d for the various run levels where you'd want to start networking automatically.

Currently I am making ethernet configuration and activation in init script. To me this is not sufficient as I want to have networking ready asap. Ethernet setup relatively takes a long time about 3s, so I want to start this operation earlier.
I am not using any of the autoconfiguration protocols: bootp, dhcp or rarp. Also, I am using ramdisk (not nfs) and macb.c driver.

Would any type of pxe or gpxe do?