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):
  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         stylesheet_result = style.saveResultToString(result)
  27         style.freeStylesheet()
  28         doc.freeDoc()
  29         result.freeDoc()
  30
  31         return stylesheet_result
  32
  33     def match(self, rspec):
  34         match_result = self.apply_processor('match',rspec)
  35         return (match_result=='True')
  36
  37     def target(self, rspec):
  38         target_result = self.apply_processor('target',rspec)
  39         return target_result
  40
  41     def apply_interpreted(self, rspec):
  42         # Interpreted
  43         #
  44         # output =
  45         #    if (match(match_args, rspec)
  46         #       then target(target_args, rspec)
  47         #       else rspec
  48
  49         if (self.match(rspec)):
  50             return self.target(rspec)
  51         else:
  52             return rspec
  53
  54
  55     def apply_compiled(rspec):
  56         # Not supported yet
  57         return None
  58
  59     def load_xml_extension (self, type, chain, rule_number):
  60         filename = sfatables_config+"/"+chain+"/"+"sfatables-%d-%s"%(rule_number,type)
  61
  62         self.xmldoc = libxml2.parseFile(filename)
  63         p = self.xmldoc.xpathNewContext()
  64
  65         context = p.xpathEval('//context/@select')
  66         self.context[type] = context[0].content
  67
  68         processor = p.xpathEval('//processor/@filename')
  69
  70         context = p.xpathEval('//attributes/attribute[@terminal="yes"]')
  71         if (context != []):
  72             self.terminal = 1
  73
  74         self.processors[type] = processor[0].content
  75         self.arguments[type] = p.xpathEval('//rule')
  76
  77         p.xpathFreeContext()
  78
  79
  80     def wrap_rspec (self, type, rspec):
  81         argument = self.arguments[type]
  82         p = rspec.xmldoc.xpathNewContext()
  83         root_node = p.xpathEval('/RSpec')
  84         if (not root_node or not root_node):
  85             raise Exception('An evil aggregate manager sent me a malformed RSpec. Please see the stack trace to identify it.')
  86
  87         root_node.addChild(arguments[type])
  88         return rspec
  89
  90     def __init__(self, chain, rule_number):
  91
  92         self.load_xml_extension('match', chain, rule_number)
  93         self.load_xml_extension('target',chain, rule_number)
  94         self.rule_number = rule_number
  95         self.chain = chain
  96
  97         return
  98
  99     def free(self):
 100         self.xmldoc.freeDoc()