dhclient 4.1.1 fails to find any interfaces

[Chad Monroe]

Hi all,

I have dhclient 3.1.2p1 successfully running on my linux 2.4.21 based 
platform without issue. In testing dhclient 4.1.1 I've run into an 
interesting issue. When starting dhclient 4.1.1 with the exact same 
config I receive the following:

Internet Systems Consortium DHCP Client 4.1.1
Copyright 2004-2010 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

No broadcast interfaces found - exiting.

After stumbling around a bit I found that if I put an IP on the 
interface I want to DHCP on, dhclient finds it, starts up, and DHCPs 
successfully. I've tried configuring the interfaces with an IP of 
0.0.0.0 but it still fails. I started looking through the code and found 
the culprit in common/discover.c around line 560. An ioctl() call is 
made for SIOCGIFADDR on each interface. On my platform this fails unless 
the interface has a valid IP. If this fails, the ioctl() for 
SIOCGIFFLAGS is never made, therefor the flags for the interface will be 
invalid (ie IFF_BROADCAST flag not set). Is this a known bug, or 
possibly caused by a mis-configuration on my system? Thanks!

     -Chad