mininet.net.Mininet

模拟一个 Mininet 中的网络，包括拓扑、交换机、主机、控制器、链路、接口等。
其中最主要的部分是 build() 函数，依次执行：根据拓扑创建网络，配置网络名字空间，配置主机的 IP、MAC 等信息，检查是否启动 xterm，是否配置自动静态 arp 等。

init

  1.           inNamespace=False,
  2.                   autoSetMacs=False, autoStaticArp=False, autoPinCpus=False,
  3.                   listenPort=None ):
  4.         """Create Mininet object.
  5.            topo: Topo (topology) object or None
  6.            switch: default Switch class
  7.            host: default Host class/constructor
  8.            controller: default Controller class/constructor
  9.            link: default Link class/constructor
  10.            intf: default Intf class/constructor
  11.            ipBase: base IP address for hosts,
  12.            build: build now from topo?
  13.            xterms: if build now, spawn xterms?
  14.            cleanup: if build now, cleanup before creating?
  15.            inNamespace: spawn switches and controller in net namespaces?
  16.            autoSetMacs: set MAC addrs automatically like IP addresses?
  17.            autoStaticArp: set all-pairs static MAC addrs?
  18.            autoPinCpus: pin hosts to (real) cores (requires CPULimitedHost)?
  19.            listenPort: base listening port to open; will be incremented for
  20.                each additional switch in the net if inNamespace=False"""
  21.         self.topo = topo
  22.         self.switch = switch
  23.         self.host = host
  24.         self.controller = controller
  25.         self.link = link
  26.         self.intf = intf
  27.         self.ipBase = ipBase
  28.         self.ipBaseNum, self.prefixLen = netParse( self.ipBase )
  29.         self.nextIP = 1  # start for address allocation
  30.         self.inNamespace = inNamespace
  31.         self.xterms = xterms
  32.         self.cleanup = cleanup
  33.         self.autoSetMacs = autoSetMacs
  34.         self.autoStaticArp = autoStaticArp
  35.         self.autoPinCpus = autoPinCpus
  36.         self.numCores = numCores()
  37.         self.nextCore = 0  # next core for pinning hosts to CPUs
  38.         self.listenPort = listenPort
  40.         self.hosts = []
  41.         self.switches = []
  42.         self.controllers = []
  44.         self.nameToNode = {}  # name to Node (Host/Switch) objects
  46.         self.terms = []  # list of spawned xterm processes
  48.         Mininet.init()  # Initialize Mininet if necessary
  50.         self.built = False
  51.         if topo and build:
  52.             self.build()

该方法主要根据传入参数配置相关的数据结构。如果还通过参数执行了拓扑信息，则执行 build 方法，调用 buildFromTopo 方法来根据拓扑信息创建节点和相关的连接等。

buildFromTopo

  1. def buildFromTopo( self, topo=None ):
  2.         """Build mininet from a topology object
  3.            At the end of this function, everything should be connected
  4.            and up."""
  6.         # Possibly we should clean up here and/or validate
  7.         # the topo
  8.         if self.cleanup:
  9.             pass
  11.         info( '*** Creating network\n' )
  13.         if not self.controllers and self.controller:
  14.             # Add a default controller
  15.             info( '*** Adding controller\n' )
  16.             classes = self.controller
  17.             if type( classes ) is not list:
  18.                 classes = [ classes ]
  19.             for i, cls in enumerate( classes ):
  20.                 self.addController( 'c%d' % i, cls )
  22.         info( '*** Adding hosts:\n' )
  23.         for hostName in topo.hosts():
  24.             self.addHost( hostName, **topo.nodeInfo( hostName ) )
  25.             info( hostName + ' ' )
  27.         info( '\n*** Adding switches:\n' )
  28.         for switchName in topo.switches():
  29.             self.addSwitch( switchName, **topo.nodeInfo( switchName) )
  30.             info( switchName + ' ' )
  32.         info( '\n*** Adding links:\n' )
  33.         for srcName, dstName in topo.links(sort=True):
  34.             src, dst = self.nameToNode[ srcName ], self.nameToNode[ dstName ]
  35.             params = topo.linkInfo( srcName, dstName )
  36.             srcPort, dstPort = topo.port( srcName, dstName )
  37.             self.addLink( src, dst, srcPort, dstPort, **params )
  38.             info( '(%s, %s) ' % ( src.name, dst.name ) )
  40.         info( '\n' )