Add option to turn off passive listening port

bin/mn

@@ -179,6 +179,8 @@ class MininetRunner( object ):
         opts.add_option( '--listenport', type='int', default=6634,
                         help='[base port for passive switch listening'
                         ' controller]' )
+        opts.add_option( '--nolistenport', action='store_true',
+                        default=False, help="don't use passive listening port")
         opts.add_option( '--pre', type='string', default=None,
                         help='[CLI script to run before tests]' )
         opts.add_option( '--post', type='string', default=None,
@@ -225,6 +227,8 @@ class MininetRunner( object ):
         xterms = self.options.xterms
         mac = self.options.mac
         arp = self.options.arp
+        listenPort = None
+        if not self.options.nolistenport:
             listenPort = self.options.listenport
         mn = Mininet( topo, switch, host, controller, controllerParams,
                      inNamespace=inNamespace,

mininet/net.py

@@ -174,7 +174,7 @@ class Mininet( object ):
             sw = self.switch( name, listenPort=self.listenPort,
                 defaultMAC=mac, defaultIP=ip, dp=self.dps,
                 inNamespace=self.inNamespace )
-        if not self.inNamespace:
+        if not self.inNamespace and self.listenPort:
             self.listenPort += 1
         self.dps += 1
         self.switches.append( sw )