基类 - Mininet 应用与源码剖析

即 mininet.node.Node， 表示一个基本的虚拟网络节点，是所有的网络节点的父类。
实现上其实就是在网络名字空间中的一个shell进程，可以通过各种管道进行通信。该类是模块中其他类的根本，其它类都是直接或间接继承。
节点包括名称、是否在网络名字空间、接口、端口等可能的属性。
init
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   params: Node parameters (see config() for details)"""
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​
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        # Make sure class actually works
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        self.checkSetup()
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​
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        self.name = name
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        self.inNamespace = inNamespace
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​
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        # Stash configuration parameters for future reference
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        self.params = params
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​
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        self.intfs = {}  # dict of port numbers to interfaces
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        self.ports = {}  # dict of interfaces to port numbers
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                         # replace with Port objects, eventually ?
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        self.nameToIntf = {}  # dict of interface names to Intfs
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​
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        # Make pylint happy
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        ( self.shell, self.execed, self.pid, self.stdin, self.stdout,
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            self.lastPid, self.lastCmd, self.pollOut ) = (
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                None, None, None, None, None, None, None, None )
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        self.waiting = False
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        self.readbuf = ''
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​
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        # Start command interpreter shell
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        self.startShell()
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初始化函数主要进行参数的初始化，之后通过调用 startShell() 启动一个 shell进程（该进程默认关闭描述符，并从 tty 上分离开来），等待接受传入的命令。句柄被发送给 self.shell 上。
addIntf
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def addIntf( self, intf, port=None ):
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        """Add an interface.
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           intf: interface
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           port: port number (optional, typically OpenFlow port number)"""
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        if port is None:
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            port = self.newPort()
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        self.intfs[ port ] = intf
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        self.ports[ intf ] = port
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        self.nameToIntf[ intf.name ] = intf
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        debug( '\n' )
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        debug( 'added intf %s:%d to node %s\n' % ( intf, port, self.name ) )
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        if self.inNamespace:
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            debug( 'moving', intf, 'into namespace for', self.name, '\n' )
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            moveIntf( intf.name, self )
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添加一个接口（比如 <Intf h1-eth0> ）到节点上，如果给定了 port（比如 0 ），则建立端口到接口的映射关系。这个映射关系通过 self.intfs 和 self.ports 两个字典来分别维护。
cmd
该函数能在节点所在的进程shell上执行输入的命令。
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def cmd( self, *args, **kwargs ):
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        """Send a command, wait for output, and return it.
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           cmd: string"""
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        verbose = kwargs.get( 'verbose', False )
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        log = info if verbose else debug
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        log( '*** %s : %s\n' % ( self.name, args ) )
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        self.sendCmd( *args, **kwargs )
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        return self.waitOutput( verbose )
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config
配置 MAC，IP 或 default Route 信息。
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def config( self, mac=None, ip=None,
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                defaultRoute=None, lo='up', **_params ):
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        """Configure Node according to (optional) parameters:
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           mac: MAC address for default interface
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           ip: IP address for default interface
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           ifconfig: arbitrary interface configuration
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           Subclasses should override this method and call
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           the parent class's config(**params)"""
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        # If we were overriding this method, we would call
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        # the superclass config method here as follows:
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        # r = Parent.config( **_params )
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        r = {}
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        self.setParam( r, 'setMAC', mac=mac )
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        self.setParam( r, 'setIP', ip=ip )
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        self.setParam( r, 'setDefaultRoute', defaultRoute=defaultRoute )
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        # This should be examined
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        self.cmd( 'ifconfig lo ' + lo )
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        return r
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connectionsTo
返回所有从自身连接到给定节点的接口，即 [ intf1, intf2... ]。
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def connectionsTo( self, node):
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        "Return [ intf1, intf2... ] for all intfs that connect self to node."
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        # We could optimize this if it is important
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        connections = []
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        for intf in self.intfList():
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            link = intf.link
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            if link:
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                node1, node2 = link.intf1.node, link.intf2.node
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                if node1 == self and node2 == node:
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                    connections += [ ( intf, link.intf2 ) ]
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                elif node1 == node and node2 == self:
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                    connections += [ ( intf, link.intf1 ) ]
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        return connections
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mininet.node 模块
主机类
Last modified 2yr ago
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