root/branch/UMPA/umpa/protocols/IP.py @ 3128

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Copyright (C) 2008 Adriano Monteiro Marques.
#
# Author: Bartosz SKOWRON <getxsick at gmail dot com>
#
# This library is free software; you can redistribute it and/or modify 
# it under the terms of the GNU Lesser General Public License as published 
# by the Free Software Foundation; either version 2.1 of the License, or 
# (at your option) any later version.
#
# This library is distributed in the hope that it will be useful, but 
# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
# or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
# License for more details.
#
# You should have received a copy of the GNU Lesser General Public License 
# along with this library; if not, write to the Free Software Foundation, 
# Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 

import base
from umpa.utils.my_exceptions import UMPAAttributeException

class HVersion(base.Field):
    def fillout(self):
        pass

class HIHL(base.Field):
    def fillout(self):
        pass

class HTypeOfService(base.Field):
    def fillout(self):
        pass

class HTotalLength(base.Field):
    def fillout(self):
        pass

class HIdentification(base.Field):
    def fillout(self):
        pass

class HFlags(base.Flags):
    def fillout(self):
        pass

class HFragmentOffset(base.Field):
    def fillout(self):
        pass

class HTimeToLive(base.Field):
    def fillout(self):
        pass

class HProtocol(base.Field):
    def fillout(self):
        pass

class HHeaderChecksum(base.Field):
    def fillout(self):
        pass

class HSourceAddress(base.Field):
    def fillout(self):
        pass

class HDestinationAddress(base.Field):
    def fillout(self):
        pass

class HOptions(base.Field):
    def fillout(self):
        pass

class HPadding(base.Field):
    def fillout(self):
        pass

# main IP class

class IP(base.Protocol):
    _ordered_fields = ('_version', '_ihl', 'type_of_service', '_total_length',
                        'identification', 'flags', '_fragment_offset',
                        'time_to_live', 'protocol', '_header_checksum',
                        'source_address', 'destination_address', 'options',
                        '_padding',)

    def __init__(self, **kw):
        base.Protocol.__init__(self, kw)

        fields_list = [ HVersion(4, True), HIHL(4, True),
                        HTypeOfService(8), HTotalLength(16, True),
                        HIdentification(16, True), HFlags(3, True), # add names to flags later
                        HFragmentOffset(13, True), HTimeToLive(8),
                        HProtocol(8, True), HHeaderChecksum(16, True),
                        HSourceAddress(16), HDestinationAddress(16),
                        HOptions(0), HPadding(0, True), ]

        # we pack objects of header's fields to the dict
        self._fields = dict(zip(self._ordered_list, fields_list))

        # setting up passed fields
        for field in kw:
            self.__setattr__(field, kw[field])

    def _is_valid(self, name):
        """Check if attribute is allowed."""
        return self._fields.has_key(name)

    def __setattr__(self, attr, val):
        """Set value of the field."""

        # we can do the same without _is_valid() with just try/except section
        # but Francesco asked me about this method
        if self._is_valid(attr):
            self._fields[attr].set(val)
        else:
            raise UMPAAttributeException, attr + ' not allowed'

    def __getattr__(self, attr):
        """Return value of the field."""
        if self._is_valid(attr):
            return self._fields[attr].get()
        else:
            raise UMPAAttributeException, attr + ' not allowed'