* 'flow' reflects the flow information for 'packet'. All of the
* information in 'flow' is extracted from 'packet', except for
* flow->tun_id and flow->in_port, which are assigned the correct values
* 'flow' reflects the flow information for 'packet'. All of the
* information in 'flow' is extracted from 'packet', except for
* flow->tun_id and flow->in_port, which are assigned the correct values