1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
|
# Copyright (c) 2006, 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: dns.py,v 1.4 2006/09/01 07:45:56 gnn Exp $
#
# Author: George V. Neville-Neil
#
# Description: DNS Packet Class
import pcs
class dnsheader(pcs.Packet):
layout = pcs.Layout()
def __init__(self, bytes = None):
"""Define the fields of a DNS (RFC 1035) header"""
length = pcs.Field("length", 16)
id = pcs.Field("id", 16)
query = pcs.Field("query", 1)
opcode = pcs.Field("opcode", 4)
aa = pcs.Field("aa", 1)
tc = pcs.Field("tc", 1)
rd = pcs.Field("rd", 1)
ra = pcs.Field("ra", 1)
z = pcs.Field("z", 3, default = 0)
rcode = pcs.Field("rcode", 4)
qdcount = pcs.Field("qdcount", 16)
ancount = pcs.Field("ancount", 16)
nscount = pcs.Field("nscount", 16)
arcount = pcs.Field("arcount", 16)
pcs.Packet.__init__(self,
[length, id, query, opcode, aa, tc, rd, ra, z,
rcode, qdcount, ancount, nscount, arcount],
bytes = bytes)
self.description = "DNS Header"
class dnslabel(pcs.Packet):
"""A DNS Label."""
layout = pcs.Layout()
def __init__(self, bytes = None):
"""initialize a DNS label, which is a component of a domain name"""
name = pcs.LengthValueField("name", 8)
pcs.Packet.__init__(self,
[name],
bytes = bytes)
self.description = "DNS Label"
class dnsquery(pcs.Packet):
"""A DNS query class"""
layout = pcs.Layout()
def __init__(self, bytes = None):
"""initialize a DNS query packet, which is a query for information"""
type = pcs.Field("type", 16)
qclass = pcs.Field("query_class", 16)
pcs.Packet.__init__(self,
[type, qclass],
bytes = bytes)
self.description = "DNS Query"
class dnsrr(pcs.Packet):
"""A DNS Resource Record"""
layout = pcs.Layout()
def __init__(self, bytes = None):
"""initialize a DNS resource record, which encodes data returned from a query"""
name = pcs.LengthValueField("name", 8)
type = pcs.Field("type", 16)
qclass = pcs.Field("query_class", 16)
ttl = pcs.Field("ttl", 16)
rdata = pcs.LengthValueField("rdata", 16)
pcs.Packet.__init__(self,
[name, type, qclass, ttl, rdata],
bytes = bytes)
self.description = "DNS Resource Record"
|
