Changeset 3221

Timestamp:

07/26/08 03:30:11 (5 years ago)

Author:

getxsick

Message:

Implemented Padding in IP protocol.

New class PaddingField? (subclass of Field).
_value keeps length of padding, and padding bits are 0.

Location:

branch/UMPA/umpa/protocols

Files:

• IP.py (modified) (3 diffs)
• _.py (modified) (2 diffs)

branch/UMPA/umpa/protocols/IP.py

@@ -134 +134 @@
         pass
 
-class HPadding(IntField):
+class HPadding(PaddingField):
     """The internet header padding is used to ensure that the internet header
     ends on a 32 bit boundary.
@@ -142 +142 @@
     bits = 0
     auto = True
-    def _generate_value(self):
-        pass
+
+    def __init__(self, *args, **kwds):
+        super(HIHL, self).__init__(*args, **kwds)
+        self._temp_value = 0
+
+    def _generate_value(self):
+        return (32 - (self._temp_value % 32)) % 32
 
 # main IP class
@@ -216 +221 @@
         raw_value = 0
 
+        # Padding
+        self._fields['_padding']._temp_value = self._fields['options'].bits
+
         # IHL
         # we store sum of option and padding bits in the _temp_value

branch/UMPA/umpa/protocols/_.py

@@ -93 +93 @@
         """Check if a value is not bigger than expected.
         """
+
         if 2**self.bits > val:
             return True
@@ -131 +132 @@
         return raw
 
+class PaddingField(IntField):
+    def _is_valid(self, val):
+        if isinstance(val, int):
+            return True
+        return False
+
+    def fillout(self):
+        self._pre_fillout()
+
+        if not self._value:
+            self.bits = self._generate_value()
+        else:
+            self.bits = self._value
+        return self._raw_value()
+    
+    def _raw_value(self):
+        return 0
 
 class Flags(Field):