Note to QE: this should probably be verified in conjunction with the original OSP bug: https://bugzilla.redhat.com/show_bug.cgi?id=1801006 (the original bug is marked as TestOnly).

verified on version:
# rpm -qa|grep ovn
ovn2.12-2.12.0-36.el7fdp.x86_64
ovn2.12-host-2.12.0-36.el7fdp.x86_64
ovn2.12-central-2.12.0-36.el7fdp.x86_64




:: [ 01:06:03 ] :: [  BEGIN   ] :: Running 'ip netns exec vm2 /usr/libexec/platform-python ./broadcastset.py'
.
Sent 1 packets.
:: [ 01:06:04 ] :: [   PASS   ] :: Command 'ip netns exec vm2 /usr/libexec/platform-python ./broadcastset.py' (Expected 0, got 0)
:: [ 01:06:09 ] :: [  BEGIN   ] :: Running 'tcpdump -r a.pacp -nn -v |grep 42.42.42.254.67.*255.255.255.255.*BOOTP/DHCP.*Reply'
reading from file a.pacp, link-type EN10MB (Ethernet)
    42.42.42.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 276, Flags [Broadcast]
:: [ 01:06:09 ] :: [   PASS   ] :: Command 'tcpdump -r a.pacp -nn -v |grep 42.42.42.254.67.*255.255.255.255.*BOOTP/DHCP.*Reply' (Expected 0, got 0)


send dhcp discovery with broadcast flag:
conf.checkIPaddr = False
    fam,hw =get_if_raw_hwaddr(conf.iface)
    sendp(Ether(src="00:00:00:00:00:02", dst="ff:ff:ff:ff:ff:ff")/IP(src="0.0.0.0", dst="255.255.255.255")/UDP(sport=68,dport=67)/BOOTP(flags=32768,chaddr=hw)/DHCP(options=[("message-type","discover"),"end"]),iface="vm2")
and recieve the server reply in broadcast.
tcpdump -r a.pacp -nn -v |grep 42.42.42.254.67.*255.255.255.255.*BOOTP/DHCP.*Reply'
reading from file a.pacp, link-type EN10MB (Ethernet)
    42.42.42.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 276, Flags [Broadcast]

ovn2.12 has been superceded by ovn2.13.