DHCP broadcasts are not leaving the interface

[Diman]

Hi All,
I  am  trying  to  setup up freeradius as dchp server. Everything is Ok,
exempt broadcast packets (dhcp offers) are not leaving the server interface.
I use Ubuntu 14.04.2 LTS (GNU/Linux 3.13.0-45-generic i686) and
FreeRADIUS   Version  2.2.7,compiled  from  git  v2.x.x  sources.
Firewall is off, radiusd runs as root.

strace  shows  some sendto() errors like: EACCES (Permission denied)
and EINVAL (Invalid argument).

The    EINVAL    (Invalid    argument)    could    be    fixed    with
"--without-udpfromto" compile option.

The full details are available at http://pastebin.com/625BEbr1

I  have  not a programmer at all, but my suspicion is that send socket
option SO_BROADCAST is not set ... not sure. Unicast replies are Ok.

My questions are: what else should I check? is there any workaround for
this issue?

Thanks.
Dmitri