sfatables/xmlrule.py

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