Traffic Monitor源碼分析

從simple_switch_13.SimpleSwitch13控制器繼承並開發

class SimpleMonitor13(simple_switch_13.SimpleSwitch13):

增添datapaths列表，存儲交換機id

def __init__(self, *args, **kwargs):
    super(SimpleMonitor13, self).__init__(*args, **kwargs)
    self.datapaths = {}

引入hub.spawn()函數啟動一個新線程，輸入為一個新的方法_monitor。

創建一個EventOFPStateChange監聽事件，監聽MAIN_DISPATCHER,DEAD_DISPATCHER兩種情況。

@set_ev_cls(ofp_event.EventOFPStateChange,
                [MAIN_DISPATCHER, DEAD_DISPATCHER])

監聽如果為MAIN_DISPATCHER,並且datapath.id不在datapath列表中，則證明是新加入的交換機

if ev.state == MAIN_DISPATCHER:
      if datapath.id not in self.datapaths:
           self.logger.debug(‘register datapath: %016x‘, datapath.id)
           self.datapaths[datapath.id] = datapath
 

如果為DEAD_DISPATCHER，並且datapath.id在datapath列表中，則證明是掉線的交換機

 elif ev.state == DEAD_DISPATCHER:
        if datapath.id in self.datapaths:
            self.logger.debug(‘unregister datapath: %016x‘, datapath.id)
            del self.datapaths[datapath.id]

_monitor方法，循環不斷向datapath列表中的交換機發送Flow狀態請求，和Port狀態請求

def _monitor(self):
    while True:
        for dp in self.datapaths.values():
            self._request_stats(dp)
        hub.sleep(10)

def _request_stats(self, datapath):
      self.logger.debug(‘send stats request: %016x‘, datapath.id)
      ofproto = datapath.ofproto
      parser = datapath.ofproto_parser

      req = parser.OFPFlowStatsRequest(datapath)
      datapath.send_msg(req)

      req = parser.OFPPortStatsRequest(datapath, 0, ofproto.OFPP_ANY)
      datapath.send_msg(req)

剛剛發送了請求，現在監聽其回復

@set_ev_cls(ofp_event.EventOFPFlowStatsReply, MAIN_DISPATCHER)
...

@set_ev_cls(ofp_event.EventOFPPortStatsReply, MAIN_DISPATCHER)
...

打印返回的信息

for stat in sorted([flow for flow in body if flow.priority == 1],
                   key=lambda flow: (flow.match[‘in_port‘],
                                     flow.match[‘eth_dst‘])):
    self.logger.info(‘%016x %8x %17s %8x %8d %8d‘,
                     ev.msg.datapath.id,
                     stat.match[‘in_port‘], stat.match[‘eth_dst‘],
                     stat.instructions[0].actions[0].port,
                     stat.packet_count, stat.byte_count)

...
for stat in sorted(body, key=attrgetter(‘port_no‘)):
     self.logger.info(‘%016x %8x %8d %8d %8d %8d %8d %8d‘,
          ev.msg.datapath.id, stat.port_no,
          stat.rx_packets, stat.rx_bytes, stat.rx_errors,
          stat.tx_packets, stat.tx_bytes, stat.tx_errors)

其中sorted ... lambda語法，指元組的排列順序按照先in_port再eth_dst

至此，整個程序解析完畢。

Traffic Monitor源碼分析