Ryu源码之拓扑发现原理分析

参考：Ryu拓扑发现原理分析（ryu/topology/switches.py)，通过对该文件的分析，可以更好的了解数据平面中设备信息

（一）Port类

class Port(object):
    # This is data class passed by EventPortXXX
    def __init__(self, dpid, ofproto, ofpport):
        super(Port, self).__init__()

        self.dpid = dpid
        self._ofproto = ofproto
        self._config = ofpport.config
        self._state = ofpport.state

        self.port_no = ofpport.port_no
        self.hw_addr = ofpport.hw_addr
        self.name = ofpport.name

    def is_reserved(self):
        return self.port_no > self._ofproto.OFPP_MAX

    def is_down(self):
        return (self._state & self._ofproto.OFPPS_LINK_DOWN) > 0 \
            or (self._config & self._ofproto.OFPPC_PORT_DOWN) > 0

    def is_live(self):
        # NOTE: OF1.2 has OFPPS_LIVE state
        #       return (self._state & self._ofproto.OFPPS_LIVE) > 0
        return not self.is_down()

    def to_dict(self):
        return {'dpid': dpid_to_str(self.dpid),
                'port_no': port_no_to_str(self.port_no),
                'hw_addr': self.hw_addr,
                'name': self.name.decode('utf-8')}

    # for Switch.del_port()
    def __eq__(self, other):
        return self.dpid == other.dpid and self.port_no == other.port_no

    def __ne__(self, other):
        return not self.__eq__(other)

    def __hash__(self):
        return hash((self.dpid, self.port_no))

    def __str__(self):
        LIVE_MSG = {False: 'DOWN', True: 'LIVE'}
        return 'Port<dpid=%s, port_no=%s, %s>' % \
            (self.dpid, self.port_no, LIVE_MSG[self.is_live()])

class Port(object):