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# Copyright (c) 2005, Neville-Neil Consulting
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# Neither the name of Neville-Neil Consulting nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
# File: $Id: udpv6.py,v 1.1 2006/07/06 09:31:57 gnn Exp $
#
# Author: George V. Neville-Neil
#
# Description: A class which implements UDP v6 packets
import sys
sys.path.append("../src")
import pcs
from pseudoipv6 import *
class udpv6(pcs.Packet):
layout = pcs.Layout()
def __init__(self, bytes = None):
"""Initialize a UDP packet for IPv6"""
sport = pcs.Field("sport", 16)
dport = pcs.Field("dport", 16)
length = pcs.Field("length", 16)
checksum = pcs.Field("checksum", 16)
pcs.Packet.__init__(self, [sport, dport, length, checksum], bytes)
def cksum(self, ip, data = "", nx = 0):
"""return udpv6 checksum"""
total = 0
p6 = pseudoipv6()
p6.src = ip.src
p6.dst = ip.dst
p6.length = len(self.getbytes()) + len (data)
if nx:
p6.next_header = nx
else:
p6.next_header = ip.next_header
pkt = p6.getbytes() + self.getbytes() + data
if len(pkt) % 2 == 1:
pkt += "\0"
for i in range(len(pkt)/2):
total += (struct.unpack("!H", pkt[2*i:2*i+2])[0])
total = (total >> 16) + (total & 0xffff)
total += total >> 16
return ~total
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