Added RegexpQuery

With RegexpQuery, it's possible to register callbacks on string matches.

Author: SiGe

pyretic/examples/regexp.py

@@ -0,0 +1,53 @@
+################################################################################
+# 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.                               #
+################################################################################
+
+################################################################################
+# SETUP                                                                        #
+# -------------------------------------------------------------------          #
+# mininet: mininet.sh --topo=single,3,3 (or other single subnet network)       #
+# test:    h1 python2 -m SimpleHTTPServer 3000                                 #
+#          h2 curl 10.0.0.1:3000                                               #
+#                                                                              #
+#          It should output:                                                   #
+#                                                                              #
+################################################################################
+
+from pyretic.lib.corelib import *
+from pyretic.lib.std import *
+from pyretic.lib.query import *
+from pyretic.modules.mac_learner import mac_learner
+
+def print_urls(pkt, match):
+    print 'verb: %-5s | path: %-25s | version: %-3s' % match.groups()
+        
+### Main ###
+def main():
+    re = RegexpQuery("(?P<verb>GET|POST|DELETE|PUT|HEAD)\s*(?P<path>.*?)\s*HTTP/(?P<http>.*?)\n")
+    re.register_callback(print_urls)
+
+    return mac_learner() + re

pyretic/lib/query.py

@@ -26,8 +26,9 @@
 # permissions and limitations under the License.                               #
 ################################################################################
 
-from pyretic.core.language import identity, match, union, DerivedPolicy, DynamicFilter, FwdBucket
+from pyretic.core.language import identity, match, union, DerivedPolicy, DynamicFilter, FwdBucket, Query
 import time
+import re
 from threading import Thread
 
 class LimitFilter(DynamicFilter):
@@ -145,3 +146,53 @@ class count_bytes(AggregateFwdBucket):
     """AggregateFwdBucket that calls back with aggregate bytesize of packets."""
     def aggregator(self,aggregate,pkt):
         return aggregate + pkt['header_len'] + pkt['payload_len']
+
+class RegexpQuery(Query):
+    """
+    Class for registering callbacks on matching string in packet data?
+    """
+    def __init__(self, pattern=""):
+        super(RegexpQuery, self).__init__()
+        self.re = pattern
+
+    def compile(self):
+        """Produce a Classifier for this policy
+
+        :rtype: Classifier
+        """
+        r = Rule(identity,[Controller])
+        return Classifier([r])
+
+    @property
+    def re(self):
+        return self._re
+
+    @re.setter
+    def re(self, pattern):
+        if not isinstance(pattern, re._pattern_type):
+            pattern = re.compile(pattern, re.S)
+
+        self._re = pattern
+
+    def apply(self):
+        with self.bucket_lock:
+            for pkt in self.bucket:
+                #XXX Should we go with raw data or payload?
+                #XXX Logic for iteration here? first match or all of them?
+                for m in self.re.finditer(pkt['raw']):
+                    for callback in self.callbacks:
+                        callback(pkt, m)
+
+            self.bucket.clear()
+
+    def __repr__(self):
+        return "RegexpQuery"
+
+    def __eq__(self, other):
+        # TODO: if buckets eventually have names, equality should
+        # be on names.
+        return isinstance(other, RegexpQuery) and (other.re == self.re)
+
+
+
+