# $Id: ah.py 34 2007-01-28 07:54:20Z dugsong $
# -*- coding: utf-8 -*-
"""Authentication Header."""
from __future__ import absolute_import
from . import dpkt
[docs]class AH(dpkt.Packet):
"""Authentication Header.
TODO: Longer class information....
Attributes:
__hdr__: Header fields of AH.
auth: Authentication body.
data: Message data.
"""
__hdr__ = (
('nxt', 'B', 0),
('len', 'B', 0), # payload length
('rsvd', 'H', 0),
('spi', 'I', 0),
('seq', 'I', 0)
)
auth = b''
[docs] def unpack(self, buf):
dpkt.Packet.unpack(self, buf)
self.auth = self.data[:self.len]
buf = self.data[self.len:]
from . import ip
try:
self.data = ip.IP.get_proto(self.nxt)(buf)
setattr(self, self.data.__class__.__name__.lower(), self.data)
except (KeyError, dpkt.UnpackError):
self.data = buf
def __len__(self):
return self.__hdr_len__ + len(self.auth) + len(self.data)
def __bytes__(self):
return self.pack_hdr() + bytes(self.auth) + bytes(self.data)