[openib-general] help with ifconfig output from ipoib

[Hal Rosenstock]

IPoIB hardware addresses are QPN + GID (subnet prefix and GUID). ifconfig only supports shorter HW addresses (I forget what the limit is but it is less than the 20 byte IPoIB HW address). Use the newer ip command to see the proper HW address (something like ip link show ib0).
 
-- Hal

________________________________

From: openib-general-bounces at openib.org on behalf of Ira Weiny
Sent: Tue 12/20/2005 2:21 PM
To: openib-general at openib.org
Subject: [openib-general] help with ifconfig output from ipoib



One of my coworkers brought a problem to me which I need guidance from you guys
on.

He pointed out that the HW address for the ipoib interface in ifconfig reported
all 0's.

11:12:50 > /sbin/ifconfig ib0
ib0       Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 
...

I tracked this down using strace to be a difference in the redhat kernel vs the
latest 2.6.14 kernel.  The SIOCGIFHWADDR ioctl in redhats 2.6.9 kernel will
return EOVERFLOW if the sa_data area is too small.  This seemed like an easy
enough fix.  Change the behavior of the SIOCGIFHWADDR.

I did this and this is what I got.

# ldev6 /root > /sbin/ifconfig ib0
ib0       Link encap:UNSPEC  HWaddr 00-00-04-04-FE-80-00-00-00-00-00-00-00-00-00-00 

This is not the GUID of the node?  More digging revealed that this "should"
work.  Am I incorrect in assuming that the HW address should be the node GUID?
Does this work for others?

Thanks,
Ira

PS. Sorry about the premature email before.


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