sfatables/xmlrule.py

   1 import libxml2
   2 import libxslt
   3 from sfatables.globals import *
   4
   5 class XMLRule:
   6     rule_number = None
   7     chain = None
   8     xmldoc = None
   9     terminal = 0
  10
  11     arguments = {'match':None,'target':None}
  12     processors = {'match':None,'target':None}
  13     context = {'match':None,'target':None}
  14
  15     def apply_processor(self, type, rspec, output_xpath_filter=None):
  16         processor = self.processors[type]
  17
  18         # XXX TO CLEAN UP
  19         filepath = 'processors/' + processor
  20         # XXX
  21
  22         styledoc = libxml2.parseFile(filepath)
  23         style = libxslt.parseStylesheetDoc(styledoc)
  24         doc = libxml2.parseDoc(rspec)
  25         result = style.applyStylesheet(doc, None)
  26         if (output_xpath_filter):
  27             p = result.xpathNewContext()
  28             xpath_result = p.xpathEval(output_xpath_filter)
  29             if (xpath_result == []):
  30                 raise Exception("Could not apply processor %s."%processor)
  31
  32             stylesheet_result = xpath_result[0].content
  33             p.xpathFreeContext()
  34         else:
  35             stylesheet_result = style.saveResultToString(result)
  36         style.freeStylesheet()
  37         doc.freeDoc()
  38         result.freeDoc()
  39
  40
  41         return stylesheet_result
  42
  43     def match(self, rspec):
  44         import pdb
  45         pdb.set_trace()
  46         match_result = self.apply_processor('match',rspec,"//result/@verdict")
  47         return (match_result=='True')
  48
  49     def target(self, rspec):
  50         target_result = self.apply_processor('target',rspec,None)
  51         return target_result
  52
  53     def apply_interpreted(self, rspec):
  54         # Interpreted
  55         #
  56         # output =
  57         #    if (match(match_args, rspec)
  58         #       then target(target_args, rspec)
  59         #       else rspec
  60
  61         if (self.match(rspec)):
  62             return self.target(rspec)
  63         else:
  64             return rspec
  65
  66
  67     def apply_compiled(rspec):
  68         # Not supported yet
  69         return None
  70
  71     def load_xml_extension (self, type, chain, rule_number):
  72         filename = sfatables_config+"/"+chain+"/"+"sfatables-%d-%s"%(rule_number,type)
  73
  74         self.xmldoc = libxml2.parseFile(filename)
  75         p = self.xmldoc.xpathNewContext()
  76
  77         context = p.xpathEval('//context/@select')
  78         self.context[type] = context[0].content
  79
  80         processor = p.xpathEval('//processor/@filename')
  81
  82         context = p.xpathEval('//attributes/attribute[@terminal="yes"]')
  83         if (context != []):
  84             self.terminal = 1
  85
  86         self.processors[type] = processor[0].content
  87         self.arguments[type] = p.xpathEval('//rule')
  88
  89         p.xpathFreeContext()
  90
  91
  92     def wrap_rspec (self, type, rspec):
  93         argument = self.arguments[type]
  94         p = rspec.xmldoc.xpathNewContext()
  95         root_node = p.xpathEval('/RSpec')
  96         if (not root_node or not root_node):
  97             raise Exception('An evil aggregate manager sent me a malformed RSpec. Please see the stack trace to identify it.')
  98
  99         root_node.addChild(arguments[type])
 100         return rspec
 101
 102     def __init__(self, chain, rule_number):
 103
 104         self.load_xml_extension('match', chain, rule_number)
 105         self.load_xml_extension('target',chain, rule_number)
 106         self.rule_number = rule_number
 107         self.chain = chain
 108
 109         return
 110
 111     def free(self):
 112         self.xmldoc.freeDoc()