'Unpack body in raw starting at offset.
Return new offset'

def _unpack_body(self, raw, offset, avail):

    (offset, tmp) = of._unpack('!IIIIII', raw, offset)
    self.packet_in_mask = tmp[0]
    self.packet_in_mask_slave = tmp[1]
    self.port_status_mask = tmp[2]
    self.port_status_mask_slave = tmp[3]
    self.flow_removed_mask = tmp[4]
    self.flow_removed_mask_slave = tmp[5]
    return offset
