lantz
f0c726a42f
This helps with virtualenv although it can open up another security hole if you end up using an unexpected python interpreter. Overall it seems to make sense to err on the side of usability but it's good to be aware of security. However, for the remaining utility scripts that require python 2, we explicitly note this with #!/usr/bin/python2.
96 lines
2.9 KiB
Python
Executable File
96 lines
2.9 KiB
Python
Executable File
#!/usr/bin/env python
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"""
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linuxrouter.py: Example network with Linux IP router
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This example converts a Node into a router using IP forwarding
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already built into Linux.
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The example topology creates a router and three IP subnets:
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- 192.168.1.0/24 (r0-eth1, IP: 192.168.1.1)
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- 172.16.0.0/12 (r0-eth2, IP: 172.16.0.1)
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- 10.0.0.0/8 (r0-eth3, IP: 10.0.0.1)
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Each subnet consists of a single host connected to
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a single switch:
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r0-eth1 - s1-eth1 - h1-eth0 (IP: 192.168.1.100)
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r0-eth2 - s2-eth1 - h2-eth0 (IP: 172.16.0.100)
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r0-eth3 - s3-eth1 - h3-eth0 (IP: 10.0.0.100)
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The example relies on default routing entries that are
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automatically created for each router interface, as well
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as 'defaultRoute' parameters for the host interfaces.
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Additional routes may be added to the router or hosts by
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executing 'ip route' or 'route' commands on the router or hosts.
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"""
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from mininet.topo import Topo
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from mininet.net import Mininet
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from mininet.node import Node
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from mininet.log import setLogLevel, info
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from mininet.cli import CLI
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class LinuxRouter( Node ):
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"A Node with IP forwarding enabled."
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# pylint: disable=arguments-differ
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def config( self, **params ):
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super( LinuxRouter, self).config( **params )
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# Enable forwarding on the router
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self.cmd( 'sysctl net.ipv4.ip_forward=1' )
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def terminate( self ):
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self.cmd( 'sysctl net.ipv4.ip_forward=0' )
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super( LinuxRouter, self ).terminate()
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class NetworkTopo( Topo ):
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"A LinuxRouter connecting three IP subnets"
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# pylint: disable=arguments-differ
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def build( self, **_opts ):
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defaultIP = '192.168.1.1/24' # IP address for r0-eth1
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router = self.addNode( 'r0', cls=LinuxRouter, ip=defaultIP )
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s1, s2, s3 = [ self.addSwitch( s ) for s in ( 's1', 's2', 's3' ) ]
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self.addLink( s1, router, intfName2='r0-eth1',
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params2={ 'ip' : defaultIP } ) # for clarity
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self.addLink( s2, router, intfName2='r0-eth2',
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params2={ 'ip' : '172.16.0.1/12' } )
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self.addLink( s3, router, intfName2='r0-eth3',
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params2={ 'ip' : '10.0.0.1/8' } )
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h1 = self.addHost( 'h1', ip='192.168.1.100/24',
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defaultRoute='via 192.168.1.1' )
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h2 = self.addHost( 'h2', ip='172.16.0.100/12',
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defaultRoute='via 172.16.0.1' )
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h3 = self.addHost( 'h3', ip='10.0.0.100/8',
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defaultRoute='via 10.0.0.1' )
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for h, s in [ (h1, s1), (h2, s2), (h3, s3) ]:
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self.addLink( h, s )
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def run():
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"Test linux router"
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topo = NetworkTopo()
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net = Mininet( topo=topo,
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waitConnected=True ) # controller is used by s1-s3
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net.start()
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info( '*** Routing Table on Router:\n' )
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info( net[ 'r0' ].cmd( 'route' ) )
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CLI( net )
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net.stop()
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if __name__ == '__main__':
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setLogLevel( 'info' )
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run()
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