moving NAT to nodelib

examples/natnet.py

@@ -20,7 +20,7 @@ natnet.py: Example network with NATs
 
 from mininet.topo import Topo
 from mininet.net import Mininet
-from mininet.node import NAT
+from mininet.nodelib import NAT
 from mininet.log import setLogLevel
 from mininet.cli import CLI
 from mininet.util import irange

mininet/net.py

@@ -96,7 +96,8 @@ from itertools import chain, groupby
 
 from mininet.cli import CLI
 from mininet.log import info, error, debug, output, warn
-from mininet.node import Host, OVSKernelSwitch, DefaultController, Controller, NAT
+from mininet.node import Host, OVSKernelSwitch, DefaultController, Controller
+from mininet.nodelib import NAT
 from mininet.link import Link, Intf
 from mininet.util import quietRun, fixLimits, numCores, ensureRoot
 from mininet.util import macColonHex, ipStr, ipParse, netParse, ipAdd

mininet/node.py

@@ -41,8 +41,6 @@ RemoteController: a remote controller node, which may use any
     arbitrary OpenFlow-compatible controller, and which is not
     created or managed by mininet.
 
-TODO: NAT
-
 Future enhancements:
 
 - Possibly make Node, Switch and Controller more abstract so that
@@ -1362,71 +1360,3 @@ def DefaultController( name, order=[ Controller, OVSController ], **kwargs ):
     for controller in order:
         if controller.isAvailable():
             return controller( name, **kwargs )
-
-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()
-

mininet/nodelib.py

@@ -1,15 +1,12 @@
 """
 Node Library for Mininet
 
-This contains additional Node types which you may find to be useful
+This contains additional Node types which you may find to be useful.
 """
 
-from mininet.net import Mininet
+from mininet.node import Node, Switch
-from mininet.topo import Topo
-from mininet.node import Switch
 from mininet.log import setLogLevel, info
 
-
 class LinuxBridge( Switch ):
     "Linux Bridge (with optional spanning tree)"
 
@@ -49,3 +46,70 @@ class LinuxBridge( Switch ):
         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()
+