Re: [User-mode-linux-devel] Status of Ethernet 0.0.5

[James R. L. <jl...@mi...>]

On Thu, Sep 07, 2000 at 05:01:45PM -0400, William Stearns wrote:
> Good day, James, Jeff, et al,
> 	I've had some luck with the new Ethernet code, but some things
> aren't working exactly as I'd expect.  May I bore you with the details?  
> :-)
> 	The UML is 192.168.0.12 with mac address cc0:ff:ee:c0:ff:ee, the
> host is 192.168.0.254 with mac address FE:FD:00:00:00:00.  Network 100 for
> simplicity.
> 
> In host, as root:
> ifconfig tap0 192.168.0.254 netmask 255.255.255.0 broadcast 192.168.0.255 up
> um_eth_net_util tap0 100
> Gives:
> [root@sparrow /root]# um_eth_net_util tap0 100
> /dev/tap0: No such file or directory
> PHY: tap0

I should probably have a more meaningful error message.  /dev/tap0
is required.

> 	Verrrrrrrrry Eeeeeeenteresting!  I still can't ping, but tcpdump
> is at least showing me more reasonable output; these actually look like
> arp requests.
> 	OK, why isn't the host replying?  Let's add arp to tap0 on the
> host:
> 
> ifconfig tap0 192.168.0.254 netmask 255.255.255.0 broadcast 192.168.0.255 arp up

Yep. Tap interfaces do not respond to arp by default.  It seems like that
should be a default being that it is called "ethertap" oh well.

> - Should um_eth_net_util require a real file called /dev/tap0?  If that
> file is missing, should it still work?
> 
> - Could the uml's eth0 be brought up by default with the "arp" flag
> set?  At this point I have to run the following lines before the
> networking is brought up:

I think the uml's ethernets have "arp" on by default.  I will double check.
I do know that you need to add "arp" to the tap0 interface.

> 	It would be cool if some random mac address could be assigned if
> the user doesn't assign one and the arp flag could be set
> automatically.

I would like to have a scheme for coming up with a unique MAC address, but I
haven't yet figured one out.  Any ideas?

Jim

-- 
James R. Leu