Merge pull request udacity#1 from ben-jones/assignment-7

Assignment 7

assignment-7/firewall-policies.csv

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+id,mac_0,mac_1
+1,00:00:00:00:00:01,00:00:00:00:00:02

assignment-7/pox_firewall.py

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+'''
+Coursera:
+- Software Defined Networking (SDN) course
+-- Module 4 Programming Assignment
+
+Professor: Nick Feamster
+Teaching Assistant: Muhammad Shahbaz
+'''
+
+from pox.core import core
+import pox.openflow.libopenflow_01 as of
+from pox.lib.revent import *
+from pox.lib.util import dpidToStr
+from pox.lib.addresses import EthAddr
+from collections import namedtuple
+import os
+from csv import DictReader
+
+
+log = core.getLogger()
+policyFile = "%s/pox/pox/misc/firewall-policies.csv" % os.environ[ 'HOME' ]  
+
+# Add your global variables here ... 
+
+# Note: Policy is data structure which contains a single
+# source-destination flow to be blocked on the controller.
+Policy = namedtuple('Policy', ('dl_src', 'dl_dst'))
+
+
+class Firewall (EventMixin):
+
+    def __init__ (self):
+        self.listenTo(core.openflow)
+        log.debug("Enabling Firewall Module")
+
+    def read_policies (self, file):
+        with open(file, 'r') as f:
+            reader = DictReader(f, delimiter = ",")
+            policies = {}
+            for row in reader:
+                policies[row['id']] = Policy(EthAddr(row['mac_0']), EthAddr(row['mac_1']))
+        return policies
+
+    def _handle_ConnectionUp (self, event):    
+        policies = self.read_policies(policyFile)
+        for policy in policies.itervalues():
+        # TODO: implement the code to add a rule to block the flow
+        # between the source and destination specified in each policy
+
+        # Note: The policy data structure has two fields which you can
+        # access to turn the policy into a rule. policy.dl_src will
+        # give you the source mac address and policy.dl_dst will give
+        # you the destination mac address
+
+        # Note: Set the priority for your rule to 20 so that it
+        # doesn't conflict with the learning bridge setup
+            pass
+
+        log.debug("Firewall rules installed on %s", dpidToStr(event.dpid))
+
+def launch ():
+    '''
+    Starting the Firewall module
+    '''
+    core.registerNew(Firewall)

assignment-7/pyretic_firewall.py

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+'''
+    Coursera:
+    - Software Defined Networking (SDN) course
+    -- Module 6 Programming Assignment
+    
+    Professor: Nick Feamster
+    Teaching Assistant: Muhammad Shahbaz
+'''
+
+################################################################################
+# The Pyretic Project                                                          #
+# frenetic-lang.org/pyretic                                                    #
+# author: Joshua Reich ([email protected])                               #
+################################################################################
+# Licensed to the Pyretic Project by one or more contributors. See the         #
+# NOTICES file distributed with this work for additional information           #
+# regarding copyright and ownership. The Pyretic Project licenses this         #
+# file to you under the following license.                                     #
+#                                                                              #
+# Redistribution and use in source and binary forms, with or without           #
+# modification, are permitted provided the following conditions are met:       #
+# - Redistributions of source code must retain the above copyright             #
+#   notice, this list of conditions and the following disclaimer.              #
+# - Redistributions in binary form must reproduce the above copyright          #
+#   notice, this list of conditions and the following disclaimer in            #
+#   the documentation or other materials provided with the distribution.       #
+# - The names of the copyright holds and contributors may not be used to       #
+#   endorse or promote products derived from this work without specific        #
+#   prior written permission.                                                  #
+#                                                                              #
+# Unless required by applicable law or agreed to in writing, software          #
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT    #
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the     #
+# LICENSE file distributed with this work for specific language governing      #
+# permissions and limitations under the License.                               #
+################################################################################
+
+from pyretic.lib.corelib import *
+from pyretic.lib.std import *
+
+# insert the name of the module and policy you want to import
+from pyretic.examples.pyretic_switch import act_like_switch
+from csv import DictReader
+from collections import namedtuple
+import os
+
+policy_file = "%s/pyretic/pyretic/examples/firewall-policies.csv" % os.environ[ 'HOME' ]
+Policy = namedtuple('Policy', ('mac_0', 'mac_1'))
+
+def main():
+    # Read in the policies from the firewall-policies.csv file
+    def read_policies (file):
+        with open(file, 'r') as f:
+            reader = DictReader(f, delimiter = ",")
+            policies = {}
+            for row in reader:
+                policies[row['id']] = Policy(MAC(row['mac_0']), MAC(row['mac_1']))
+        return policies
+
+    policies = read_policies(policy_file)
+
+    # start with a policy that doesn't match any packets
+    not_allowed = none
+
+    # and add traffic that isn't allowed
+    # Note: this uses the same policy named tuple from the POX
+    # firewall code. Please refer there for further info
+    for policy in policies.itervalues():
+        not_allowed = not_allowed + ( <traffic going in one direction> ) + ( <traffic going in the other direction> )
+
+    # express allowed traffic in terms of not_allowed - hint use '~'
+    allowed = <...>
+
+    # and only send allowed traffic to the mac learning (act_like_switch) logic
+    return allowed >> act_like_switch()
+
+
+