From 42cdda38bbb3a1d3950f3d42b05368bf726d8fd4 Mon Sep 17 00:00:00 2001
From: cody burkard <cody@onlab.us>
Date: Fri, 1 Aug 2014 11:27:25 -0700
Subject: [PATCH] added some documentation

---
 mininet/link.py | 11 ++++++++---
 mininet/net.py  |  2 ++
 mininet/node.py |  6 ++----
 mininet/util.py | 19 ++-----------------
 4 files changed, 14 insertions(+), 24 deletions(-)

diff --git a/mininet/link.py b/mininet/link.py
index c7e5c72..9eed928 100644
--- a/mininet/link.py
+++ b/mininet/link.py
@@ -42,6 +42,9 @@ class Intf( object ):
         self.link = link
         self.mac = mac
         self.ip, self.prefixLen = None, None
+        
+        # if interface is lo, we know the ip is 127.0.0.1.
+        # This saves an ifconfig command per node
         if self.name == 'lo':
             self.ip = '127.0.0.1'
         # Add to node (and move ourselves if necessary )
@@ -94,10 +97,12 @@ class Intf( object ):
         self.mac = macs[ 0 ] if macs else None
         return self.mac
 
+    # Instead of updating ip and mac separately,
+    # use one ifconfig call to do it simultaneously.
+    # This saves an ifconfig command, which improves performance.
+
     def updateAddr( self ):
-        """Return IP address and MAC address based on ifconfig.
-        instead of updating ip and mac separately,
-        use one ifconfig call to do it simultaneously"""
+        "Return IP address and MAC address based on ifconfig."
         ifconfig = self.ifconfig()
         ips = self._ipMatchRegex.findall( ifconfig )
         macs = self._macMatchRegex.findall( ifconfig )
diff --git a/mininet/net.py b/mininet/net.py
index 3b822f4..a3ff824 100755
--- a/mininet/net.py
+++ b/mininet/net.py
@@ -166,6 +166,7 @@ class Mininet( object ):
         if topo and build:
             self.build()
 
+
     def waitConnected( self, timeout=None, delay=.5 ):
         """wait for each switch to connect to a controller,
            up to 5 seconds
@@ -384,6 +385,7 @@ class Mininet( object ):
             srcPort, dstPort = topo.port( srcName, dstName )
             self.addLink( src, dst, srcPort, dstPort, **params )
             info( '(%s, %s) ' % ( src.name, dst.name ) )
+        
         info( '\n' )
 
     def configureControlNetwork( self ):
diff --git a/mininet/node.py b/mininet/node.py
index 0b435fc..40a3c34 100644
--- a/mininet/node.py
+++ b/mininet/node.py
@@ -331,10 +331,7 @@ class Node( object ):
         # Shell requires a string, not a list!
         if defaults.get( 'shell', False ):
             cmd = ' '.join( cmd )
-        old = signal.signal( signal.SIGINT, signal.SIG_IGN )
-        popen = Popen( cmd, **defaults )
-        signal.signal( signal.SIGINT, old )
-        return popen
+        return Popen( cmd, **defaults )
 
     def pexec( self, *args, **kwargs ):
         """Execute a command using popen
@@ -1198,6 +1195,7 @@ class IVSSwitch(Switch):
         args.append( self.opts )
 
         logfile = '/tmp/ivs.%s.log' % self.name
+        
         self.cmd( 'ifconfig lo up' )
         self.cmd( ' '.join(args) + ' >' + logfile + ' 2>&1 </dev/null &' )
 
diff --git a/mininet/util.py b/mininet/util.py
index 1bd2c5d..6c7b426 100644
--- a/mininet/util.py
+++ b/mininet/util.py
@@ -249,29 +249,14 @@ def _colonHex( val, bytecount ):
     chStr = ':'.join( pieces )
     return chStr
 
-def generateMac( self ):
-    newMac = True
-    while True:
-        macList = [ 0x00 ]
-        for i in xrange ( 0, 5 ):
-            macList.append( random.randint( 0x00, 0xff ) )
-        mac = ':'.join( map(lambda x: "%02x" % x, macList ) )
-        for node in self.switches + self.hosts:
-            for intf in node.ports:
-                if intf.mac == mac:
-                    newMac = False
-                    break
-        if newMac:
-            return mac
-
 def macColonHex( mac ):
     """Generate MAC colon-hex string from unsigned int.
        mac: MAC address as unsigned int
        returns: macStr MAC colon-hex string"""
-    if mac < 2**24:
+    if mac < 2 ** 24:
         return 'A4:23:05:' + _colonHex( mac, 3 )
     else:
-        return _colonHex( mac, 6 )
+        return 'A4:23:05:' + _colonHex( mac, 3 )
 
 def ipStr( ip ):
     """Generate IP address string from an unsigned int.