IM_l2_learning.py


#DPID = DataPath ID provded to switches that communicate with a controller
from pox.core import core
import pox.openflow.libopenflow_01 as of
from pox.lib.util import dpidToStr
from pox.lib.util import str_to_bool
import time

log = core.getLogger()

class LearningSwitch (object):
  print "\n-------------------------"
  print "----Itai's Controller----"
  print "-------------------------"
  def __init__ (self, connection):
    # Switch we'll be adding L2 learning switch capabilities to
    self.connection = connection
    connection.addListeners(self)
    self.macToPortMap = {}

  def _handle_PacketIn (self, event):
    #Parsing Incoming packet
    packet = event.parsed
    #Updating mac-table to port-mapping
    self.macToPortMap[packet.src] = event.port
    #Flooding Function
    def flood():
      print "[+] Debug: Flooding"
      msg = of.ofp_packet_out()
      msg.actions.append(of.ofp_action_output(port = of.OFPP_FLOOD))
      msg.in_port = event.port
      msg.buffer_id = event.ofp.buffer_id
      self.connection.send(msg)
    #Dropping Function
    def drop():
      print "[+] Debug: Dropping Packets"
      msg = of.ofp_flow_mod()
      msg.match = of.ofp_match.from_packet(packet)
      msg.idle_timeout = 10
      msg.hard_timeout = 30
      msg.buffer_id = event.ofp.buffer_id
      self.connection.send(msg)
    #Forwarding Function
    def forward():
      print "[+] Debug: Forwarding"
      #TODO - WILL CODE
      msg = of.ofp_flow_mod()
      msg.match.dl_src = packet.src
      msg.match.dl_dst = packet.dst
      msg.idle_timeout = 10
      msg.hard_timeout = 30
      msg.actions.append(of.ofp_action_output(port = outport))
      msg.buffer_id = event.ofp.buffer_id
      self.connection.send(msg)
    #Check if Packet has not been mapped
    if packet.dst not in self.macToPortMap:
      #switch does not know egress port
      #Flood the packet
      log.debug("[-] Debug: Port for %s unknown -- Flooding" % (packet.dst,))
      print "[+] Debug: Port for %s unknown -- Flooding" % (packet.dst,)
      flood()
    #If it has then forward the packet unless its destination is the same port its been received on
    else:
      #Forward packet if SW knows outprt
      outport = self.macToPortMap[packet.dst]
      if outport == event.port:
        log.warning("[-] Same port for packet from %s -> %s on %s/ Drop." %
                  (packet.src, packet.dst, outport), dpidToStr(event.dpid))
        print "[-] Same port for packet from %s -> %s on %s/ Drop." % (packet.src, packet.dst, outport)
        drop()
        return
      log.debug("[F] Installing flow for %s port:%i -> %sport:%i" % 
              (packet.src, event.port, packet.dst, outport), dpidToStr(event.dpid))
      print "[F] Debug: Installing flow:\n    %s port:%i -> %s port:%i \n    on Switch:" % (packet.src, event.port, packet.dst, outport), dpidToStr(event.dpid)
      log.debug("[+] Port for %s known -- Forwarding" % (packet.dst,))
      print "[+] Debug: Port for %s known -- Forwarding" % (packet.dst,)
      #Forward the packet if in MacToPortMap map
      forward()
  
class l2_learning (object):
  
  """Waits for OVSC switches and makes them learning switches"""
  
  def __init__ (self):
    core.openflow.addListeners(self)

  def _handle_ConnectionUp(self,event):
    log.debug("Connection %s" % (event.connection,))
    LearningSwitch(event.connection)

def launch ():
  
  """Starts an L2 learning switch."""
  core.registerNew(l2_learning)