Comment 16 for bug 1029430

For reference, it seems like devstack running on 3.3 or later kernel will see this. I found it running on quantal:

<adam_g> smoser: devstack doesn't configure its networks as multi_host. my fix only addresses the issue for multi_host networks, where its assumed the dhcp server is alwasy running on the same host as compute
<adam_g> smoser: devstack that just happens to be the case, but its not multihost
<adam_g> smoser: anyway, the workaround is to jus rmmod vhost_net or add the iptables mangle rule described in that bug

So specifically for devstack:
 rmmod vhost_net
or
    [ -e /dev/vhost-net ] &&
     sudo iptables -t mangle -A POSTROUTING -o br100 -p udp -m udp --dport 68 -j CHECKSUM --checksum-fill