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115 lines (92 loc) · 4 KB
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"""
Node Library for Mininet
This contains additional Node types which you may find to be useful.
"""
from mininet.node import Node, Switch
from mininet.log import setLogLevel, info
class LinuxBridge( Switch ):
"Linux Bridge (with optional spanning tree)"
nextPrio = 100 # next bridge priority for spanning tree
def __init__( self, name, stp=False, prio=None, **kwargs ):
"""stp: use spanning tree protocol? (default False)
prio: optional explicit bridge priority for STP"""
self.stp = stp
if prio:
self.prio = prio
else:
self.prio = LinuxBridge.nextPrio
LinuxBridge.nextPrio += 1
Switch.__init__( self, name, **kwargs )
def connected( self ):
"Are we forwarding yet?"
if self.stp:
return 'forwarding' in self.cmd( 'brctl showstp', self )
else:
return True
def start( self, controllers ):
self.cmd( 'ifconfig', self, 'down' )
self.cmd( 'brctl delbr', self )
self.cmd( 'brctl addbr', self )
if self.stp:
self.cmd( 'brctl setbridgeprio', self.prio )
self.cmd( 'brctl stp', self, 'on' )
for i in self.intfList():
if self.name in i.name:
self.cmd( 'brctl addif', self, i )
self.cmd( 'ifconfig', self, 'up' )
def stop( self ):
self.cmd( 'ifconfig', self, 'down' )
self.cmd( 'brctl delbr', self )
class NAT( Node ):
"""NAT: Provides connectivity to external network"""
def __init__( self, name, inetIntf='eth0', subnet='10.0/8', localIntf=None, **params):
super( NAT, self ).__init__( name, **params )
"""Start NAT/forwarding between Mininet and external network
inetIntf: interface for internet access
subnet: Mininet subnet (default 10.0/8)="""
self.inetIntf = inetIntf
self.subnet = subnet
self.localIntf = localIntf
def config( self, **params ):
super( NAT, self).config( **params )
"""Configure the NAT and iptables"""
if not self.localIntf:
self.localIntf = self.defaultIntf()
self.cmd( 'sysctl net.ipv4.ip_forward=0' )
# Flush any currently active rules
# TODO: is this safe?
self.cmd( 'iptables -F' )
self.cmd( 'iptables -t nat -F' )
# Create default entries for unmatched traffic
self.cmd( 'iptables -P INPUT ACCEPT' )
self.cmd( 'iptables -P OUTPUT ACCEPT' )
self.cmd( 'iptables -P FORWARD DROP' )
# Configure NAT
self.cmd( 'iptables -I FORWARD -i', self.localIntf, '-d', self.subnet, '-j DROP' )
self.cmd( 'iptables -A FORWARD -i', self.localIntf, '-s', self.subnet, '-j ACCEPT' )
self.cmd( 'iptables -A FORWARD -i', self.inetIntf, '-d', self.subnet, '-j ACCEPT' )
self.cmd( 'iptables -t nat -A POSTROUTING -o ', self.inetIntf, '-j MASQUERADE' )
# Instruct the kernel to perform forwarding
self.cmd( 'sysctl net.ipv4.ip_forward=1' )
# Prevent network-manager from messing with our interface
# by specifying manual configuration in /etc/network/interfaces
intf = self.localIntf
cfile = '/etc/network/interfaces'
line = '\niface %s inet manual\n' % intf
config = open( cfile ).read()
if ( line ) not in config:
info( '*** Adding "' + line.strip() + '" to ' + cfile )
with open( cfile, 'a' ) as f:
f.write( line )
# Probably need to restart network-manager to be safe -
# hopefully this won't disconnect you
self.cmd( 'service network-manager restart' )
def terminate( self ):
"""Stop NAT/forwarding between Mininet and external network"""
# Flush any currently active rules
# TODO: is this safe?
self.cmd( 'iptables -F' )
self.cmd( 'iptables -t nat -F' )
# Instruct the kernel to stop forwarding
self.cmd( 'sysctl net.ipv4.ip_forward=0' )
super( NAT, self ).terminate()