[Buildroot] busybox network configuration

[Michael S. Zick]

On Thu April 28 2011, Charles Krinke wrote:
> I think I may have over-simplified the file system as configuring
> /etc/network/interfaces doesnt work yet.
> 
> I can see via "ifconfig" and "route" that "ifup eth0" and "ifdown eth0"
> function and set the values specified in /etc/network/interfaces. I have a
> correct netmask (I oversimplified my original posting, I am actually on the
> 255.255.255.248 subnet but have tested it with both that and 255.255.255.0).
> 
> I have a lan segment with two linux hosts running debian and I can ping
> between those hosts and see with wireshark that ping request/reply packets
> are flowing.
> 
> But, when I ping from the target running the buildroot created rootfs,
> packets do not come out of the board.
> 
> In setting this up, I used the default settings in buildroot and
> consequently have a minimum number of packages. Perhaps the next question is
> "What are the minimum set of packages to specify in buildroot's config in
> order to expect an interface controlled via /etc/network/interfaces that
> does respond to ifup/ifdown require to be able to send packets out its
> interface?"
> 
> On Thu, Apr 28, 2011 at 9:30 AM, Charles Krinke <charles.krinke at gmail.com>wrote:
> 
> >
> > Thank you, Will, that gets me most of the way to the place I  need to go.
> > With this change to /etc/network/interfaces and ifconfig shows eth0 with the
> > correct ipAddress and netmask on boot. A "route" shows an appropropriate
> > valid default gateway.
> >
> > Unfortunately, ping still fails, so there must be a bit more to the recipe
> > I dont quite understand yet.
> >
> > I do know that the interface is connected and working as I can tftp u-boot,
> > uImage and rootfs.jffs2 to the board and program them into the flash. The
> > issue seems to be that the interface cannot yet ping. I will look on the
> > local lan segment with ethereal next, but I wonder if you could suggest any
> > other things to look at and consider.
> >
> >
> >
> > On Thu, Apr 28, 2011 at 8:26 AM, Will Moore <
> > will.moore at beraninstruments.com> wrote:
> >
> >> Hi Charles,
> >>
> >> > -----Original Message-----
> >> > From: buildroot-bounces at busybox.net [mailto:
> >> buildroot-bounces at busybox.net] On
> >> > Behalf Of Charles Krinke
> >> > Sent: 28 April 2011 16:16
> >> > To: buildroot
> >> > Subject: [Buildroot] busybox network configuration
> >> >
> >> > I have apparently forgotten the recipe to configure a network in
> >> busybox.
> >> >
> >> > I have tried:
> >> > # ifconfig eth0 10.1.2.3 netmask 255.255.255.0 up
> >> > # route add default gw 10.1.1.1 etho
> >> >
> >> > But, ping doesnt seem to get out of the target board.
>

You can access the network __before__ you run the kernel -
You can't access the network __while__ running the kernel.

Sounds like a NIC driver problem (or the kernel config of the NIC / network).

Being able to access the network __before__ booting the kernel
tells you that the hardware is all working and network is working.

Once Linux boots, it does not use the NIC driver built into the 
firmware of your board, it uses its own driver.

It reads as if you can see the NIC device (as eth0) -
Which usually means that the Linux driver selected recognizes the hardware.
More specific information should have appeared in the kernel boot output.

Some hardware / driver choices in the kernel configuration require
that you also option the appropriate PHY controls.
I.E: That part that electrically connects the NIC to the wire (connector).

The only supporting application you need is something to control the
kernel's interface and network settings - it reads as if you have that.
But other than for control purposes, the kernel does it all as a service
to userland, there isn't any network stack outside of the kernel to build.

So your minimum would be:
an __appropriately__ configured Linux kernel
an __appropriately__ configured Busybox (for the control applications)

If you post the output of a ping -c 3 target-ip-number we should be able
to tell from the message if packet forwarding or iptables settings
in the kernel are blocking the output.

Mike
> >> >
> >> > I also suspect there are one or more script files with things like this
> >> that
> >> > need to be set, but the busybox implementation doesnt have an
> >> > /etc/sysconfig/network-scripts, so they need to be in a different place,
> >> but
> >> > what is the location and name of the file?
> >> >
> >> > DEVICE=eth0
> >> > BOOTPROTO=static
> >> > BROADCAST=XXX.XXX.XXX.255
> >> > IPADDR=XXX.XXX.XXX.XXX
> >> > NETMASK=255.255.255.0
> >> > NETWORK=XXX.XXX.XXX.0
> >> > ONBOOT=yes
> >> >
> >> > Can someone please help my naivety a little bit with busybox, please?
> >>
> >> Just alter /etc/network/interfaces to e.g:
> >>
> >> auto eth0
> >> iface eth0 inet static
> >>   address 10.1.2.3
> >>    netmask 255.255.255.0
> >>    gateway 10.1.1.1
> >>
> >> no?
> >>
> >> >
> >> > --
> >> > Charles Krinke
> >> >
> >> >
> >>
> >>
> >>
> >>
> >
> >
> > --
> > Charles Krinke
> >
> >
> >
> 
>