Add net.delNode(), net.delLink() and associated methods

This makes the mid-level net.add*() API symmetric.
You can now delete hosts, switches, controllers and links using
a new net.del*() API, as well as del net[ 'nodename' ].

mininet/link.py

@@ -202,6 +202,8 @@ class Intf( object ):
         # if self.node.inNamespace:
         # Link may have been dumped into root NS
         # quietRun( 'ip link del ' + self.name )
+        self.node.delIntf( self )
+        self.link = None
 
     def status( self ):
         "Return intf status as a string"
@@ -471,10 +473,10 @@ class Link( object ):
     def delete( self ):
         "Delete this link"
         self.intf1.delete()
-        # We only need to delete one side, though this doesn't seem to
-        # cost us much and might help subclasses.
-        # self.intf2.delete()
-
+        self.intf1 = None
+        self.intf2.delete()
+        self.intf2 = None
+    
     def stop( self ):
         "Override to stop and clean up link as needed"
         self.delete()

mininet/net.py

@@ -226,6 +226,24 @@ class Mininet( object ):
         self.nameToNode[ name ] = h
         return h
 
+    def delNode( self, node, nodes=None):
+        """Delete node
+           node: node to delete
+           nodes: optional list to delete from (e.g. self.hosts)"""
+        if nodes is None:
+            nodes = ( self.hosts if node in self.hosts else
+                      ( self.switches if node in self.switches else
+                        ( self.controllers if node in self.controllers else
+                          [] ) ) )
+        node.stop( deleteIntfs=True )
+        node.terminate()
+        nodes.remove( node )
+        del self.nameToNode[ node.name ]
+
+    def delHost( self, host ):
+        "Delete a host"
+        self.delNode( host, nodes=self.hosts )
+
     def addSwitch( self, name, cls=None, **params ):
         """Add switch.
            name: name of switch to add
@@ -244,6 +262,10 @@ class Mininet( object ):
         self.nameToNode[ name ] = sw
         return sw
 
+    def delSwitch( self, switch ):
+        "Delete a switch"
+        self.delNode( switch, nodes=self.switches )
+
     def addController( self, name='c0', controller=None, **params ):
         """Add controller.
            controller: Controller class"""
@@ -265,6 +287,12 @@ class Mininet( object ):
             self.nameToNode[ name ] = controller_new
         return controller_new
 
+    def delController( self, controller ):
+        """Delete a controller
+           Warning - does not reconfigure switches, so they
+           may still attempt to connect to it!"""
+        self.delNode( controller )
+
     def addNAT( self, name='nat0', connect=True, inNamespace=False,
                 **params):
         """Add a NAT to the Mininet network
@@ -303,9 +331,13 @@ class Mininet( object ):
 
     # Even more convenient syntax for node lookup and iteration
     def __getitem__( self, key ):
-        """net [ name ] operator: Return node(s) with given name(s)"""
+        "net[ name ] operator: Return node with given name"
         return self.nameToNode[ key ]
 
+    def __delitem__( self, key ):
+        "del net[ name ] operator - delete node with given name"
+        self.delNode( self.nameToNode[ key ] )
+
     def __iter__( self ):
         "return iterator over node names"
         for node in chain( self.hosts, self.switches, self.controllers ):
@@ -367,6 +399,30 @@ class Mininet( object ):
         self.links.append( link )
         return link
 
+    def delLink( self, link ):
+        "Remove a link from this network"
+        link.delete()
+        self.links.remove( link )
+
+    def linksBetween( self, node1, node2 ):
+        "Return Links between node1 and node2"
+        return [ link for link in self.links
+                 if ( node1, node2 ) in (
+                    ( link.intf1.node, link.intf2.node ),
+                    ( link.intf2.node, link.intf1.node ) ) ]
+
+    def delLinkBetween( self, node1, node2, index=0, allLinks=False ):
+        """Delete link(s) between node1 and node2
+           index: index of link to delete if multiple links (0)
+           allLinks: ignore index and delete all such links (False)
+           returns: deleted link(s)"""
+        links = self.linksBetween( node1, node2 )
+        if not allLinks:
+            links = [ links[ index ] ]
+        for link in links:
+            self.delLink( link )
+        return links
+
     def configHosts( self ):
         "Configure a set of hosts."
         for host in self.hosts:
@@ -840,10 +896,8 @@ class Mininet( object ):
         elif dst not in self.nameToNode:
             error( 'dst not in network: %s\n' % dst )
         else:
-            if isinstance( src, basestring ):
-                src = self.nameToNode[ src ]
-            if isinstance( dst, basestring ):
-                dst = self.nameToNode[ dst ]
+            src = self.nameToNode[ src ]
+            dst = self.nameToNode[ dst ]
             connections = src.connectionsTo( dst )
             if len( connections ) == 0:
                 error( 'src and dst not connected: %s %s\n' % ( src, dst) )

mininet/node.py

@@ -431,6 +431,15 @@ class Node( object ):
             debug( 'moving', intf, 'into namespace for', self.name, '\n' )
             moveIntfFn( intf.name, self  )
 
+    def delIntf( self, intf ):
+        """Remove interface from Node's known interfaces
+           Note: to fully delete interface, call intf.delete() instead"""
+        port = self.ports.get( intf )
+        if port is not None:
+            del self.intfs[ port ]
+            del self.ports[ intf ]
+            del self.nameToIntf[ intf.name ]
+
     def defaultIntf( self ):
         "Return interface for lowest port"
         ports = self.intfs.keys()