sfatables/xmlrule.py

   1 import libxml2
   2 import libxslt
   3 from sfatables.globals import *
   4
   5 class XMLRule:
   6     def apply_processor(self, type, doc, output_xpath_filter=None):
   7         processor = self.processors[type]
   8
   9         # XXX TO CLEAN UP
  10         filepath = os.path.join(sfatables_config, 'processors', processor)
  11         # XXX
  12
  13         print filepath
  14         styledoc = libxml2.parseFile(filepath)
  15         style = libxslt.parseStylesheetDoc(styledoc)
  16         result = style.applyStylesheet(doc, None)
  17         if (output_xpath_filter):
  18             p = result.xpathNewContext()
  19             xpath_result = p.xpathEval(output_xpath_filter)
  20             if (xpath_result == []):
  21                 raise Exception("Could not apply processor %s."%processor)
  22
  23             stylesheet_result = xpath_result
  24             p.xpathFreeContext()
  25         else:
  26             stylesheet_result = result #style.saveResultToString(result)
  27
  28         style.freeStylesheet()
  29         #doc.freeDoc()
  30         #result.freeDoc()
  31
  32         return stylesheet_result
  33
  34     def wrap_up(self, doc):
  35         filepath = os.path.join(sfatables_config, 'processors', self.final_processor)
  36
  37         if not os.path.exists(filepath):
  38             raise Exception('Could not find final rule filter')
  39
  40         styledoc = libxml2.parseFile(filepath)
  41         style = libxslt.parseStylesheetDoc(styledoc)
  42         result = style.applyStylesheet(doc, None)
  43         stylesheet_result = result#style.saveResultToString(result)
  44         style.freeStylesheet()
  45         #doc.freeDoc()
  46         #result.freeDoc()
  47
  48         return stylesheet_result
  49
  50     def match(self, rspec):
  51         match_result = self.apply_processor('match',rspec,"//result/@verdict")
  52         return (match_result[0].content=='True')
  53
  54     def target(self, rspec):
  55         target_result = self.apply_processor('target',rspec,None)
  56         return target_result
  57
  58     def add_rule_context_to_rspec(self, doc):
  59         p = doc.xpathNewContext()
  60         context = p.xpathEval("//rspec")
  61         if (not context):
  62             raise Exception('Request is not an rspec')
  63         else:
  64             # Add the request context
  65             matchNode = libxml2.newNode('match-context')
  66             for match_argument in self.arguments['match']:
  67                 matchNode.addChild(match_argument)
  68
  69             targetNode = libxml2.newNode('target-context')
  70             for target_argument in self.arguments['target']:
  71                 targetNode.addChild(target_argument)
  72
  73             context[0].addChild(matchNode)
  74             context[0].addChild(targetNode)
  75         p.xpathFreeContext()
  76
  77         return doc
  78
  79     def apply_interpreted(self, rspec):
  80         rspec = self.add_rule_context_to_rspec(rspec)
  81         # Interpreted
  82         #
  83         # output =
  84         #    if (match(match_args, rspec)
  85         #       then target(target_args, rspec)
  86         #       else rspec
  87
  88         if (self.match(rspec)):
  89             return self.wrap_up(self.target(rspec))
  90         else:
  91             return self.wrap_up(rspec)
  92
  93
  94     def apply_compiled(rspec):
  95         # Not supported yet
  96         return None
  97
  98     def load_xml_extension (self, type, chain, rule_number):
  99         filename = sfatables_config+"/"+chain+"/"+"sfatables-%d-%s"%(rule_number,type)
 100
 101         self.xmldoc = libxml2.parseFile(filename)
 102         p = self.xmldoc.xpathNewContext()
 103
 104         context = p.xpathEval('//context/@select')
 105         self.context[type] = context[0].content
 106
 107         processor = p.xpathEval('//processor/@filename')
 108
 109         context = p.xpathEval('//attributes/attribute[@terminal="yes"]')
 110         if (context != []):
 111             self.terminal = 1
 112
 113         self.processors[type] = processor[0].content
 114         self.arguments[type] = p.xpathEval('//rule//argument[value!=""]')
 115
 116         p.xpathFreeContext()
 117
 118
 119     def __init__(self, chain=None, rule_number=None):
 120         self.rule_number = None
 121         self.chain = None
 122         self.xmldoc = None
 123         self.terminal = 0
 124         self.final_processor = '__sfatables_rule_wrap_up__.xsl'
 125
 126         self.arguments = {'match':None,'target':None}
 127         self.processors = {'match':None,'target':None}
 128         self.context = {'match':None,'target':None}
 129
 130         if (chain and rule_number):
 131             self.load_xml_extension('match', chain, rule_number)
 132             self.load_xml_extension('target',chain, rule_number)
 133             self.rule_number = rule_number
 134             self.chain = chain
 135         return
 136
 137     def free(self):
 138         self.xmldoc.freeDoc()