-
Notifications
You must be signed in to change notification settings - Fork 0
/
dns.py
214 lines (167 loc) · 5.01 KB
/
dns.py
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
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
#Copyright 2011 Matthew J. Smith (matt@forsetti.com)
#
#Licensed under the Apache License, Version 2.0 (the "License");
#you may not use this file except in compliance with the License.
#You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
#Unless required by applicable law or agreed to in writing, software
#distributed under the License is distributed on an "AS IS" BASIS,
#WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#See the License for the specific language governing permissions and
#limitations under the License.
from struct import pack,unpack
TYPES=["", "A", "NS", "", "", "CNAME",]
CLASSES=["", "IN",]
class LabelTooLong(Exception):
pass
class NameTooLong(Exception):
pass
class Name(bytearray):
def __decode__(self):
i=0
name=""
while(self[i]):
next=i+self[i]+1
name+=self[i+1:next].decode()+"."
i=next
self.__name__=name
@property
def name(self):
if(not hasattr(self,__name__)):
self.__decode__()
return(self.__name__)
def __str__(self):
return(self.name)
class StringName(Name):
def __init__(self,name, encoding="ascii"):
if(name[-1]!="."):
name+="."
self.__name__=name
labels=name.split(".")
t=bytearray(0)
for label in labels:
l=len(label)
if(l>64): raise LabelTooLong(label)
t+=bytes([len(label)])+label.encode()
if(len(self)>255): raise NameTooLong(name)
super().__init__(t)
class __ResourceRecord__(bytearray):
def __init__(self, name, rr_type, rr_class, rr_ttl, rr_rdlength, rr_rdata):
self.name=StringName(name)
self.rr_type=rr_type
self.rr_class=rr_class
self.rr_ttl=rr_ttl
self.rr_rdlength=rr_rdlength
self.rr_rdata=rr_rdata
super().__init__(self.name+pack("!HHLH",rr_type,rr_class,rr_ttl,rr_rdlength)+rr_rdata)
def __str__(self):
return("%s %s %s %s"%(self.name,TYPES[self.rr_type],CLASSES[self.rr_class],self.rr_ttl))
class CNameRR(__ResourceRecord__):
def __init__(self, name, ttl, cname):
self.cname=StringName(cname)
super().__init__(name, 5, 1, ttl, len(self.cname), self.cname)
def __str__(self):
return(super().__str__()+" "+str(self.cname))
class NSRR(__ResourceRecord__):
def __init__(self, name, ttl, nsdname):
self.nsdname=StringName(nsdname)
super().__init__(name, 2, 1, ttl, len(self.nsdname), self.nsdname)
def __str__(self):
return(super().__str__()+" "+str(self.nsdname))
class Question(bytes):
def __str__(self):
return("%s %s %s"%(self.qname,TYPES[self.qtype],CLASSES[self.qclass]))
def __decode__(self):
(self.__qtype__,self.__qclass__)=unpack("!HH",self[-4:])
self.__qname__=Name(self[:-4])
@property
def qname(self):
if(not hasattr(self,"__qname__")):
self.__decode__()
return(self.__qname__)
@property
def qtype(self):
if(not hasattr(self,"__qtype__")):
self.__decode__()
return(self.__qtype__)
@property
def qclass(self):
if(not hasattr(self,"__qclass__")):
self.__decode__()
return(self.__qclass__)
class ComponentQuestion(Question):
def __init__(self, qname, qtype, qclass=1):
super().__init__(Name(qname)+pack("!HH",qtype,qclass))
self.qname=qname
self.qtype=qtype
self.qclass=qclass
class Message(bytearray):
@property
def id(self):
return(unpack("!H",self[0:2])[0])
@property
def qr(self):
return(self[2]&0x80)
@property
def opcode(self):
return((self[2]&0x78)>>3)
@property
def aa(self):
return(self[2]&0x04)
@property
def tc(self):
return(self[2]&0x02)
@property
def rd(self):
return(self[2]&0x01)
@property
def ra(self):
return(self[3]&0x80)
@property
def z(self):
return((self[3]&0x70)>>4)
@property
def rcode(self):
return(self[3]&0x0F)
@property
def qdcount(self):
return(unpack("!H",self[4:6])[0])
@property
def ancount(self):
return(unpack("!H",self[6:8])[0])
@property
def nscount(self):
return(unpack("!H",self[8:10])[0])
@property
def arcount(self):
return(unpack("!H",self[10:12])[0])
@property
def questions(self):
q1=12
q2=q1
for qdcount in range(self.qdcount):
while(self[q2]):
q2+=self[q2]+1
q2+=4
yield(Question(self[q1:q2+1]))
q1=q2
def __str__(self):
return("ID:%s OPCODE:%s RCODE:%s "%(self.id,self.opcode,self.rcode)+("qr " if self.qr else "")+("aa " if self.aa else "")+("tc " if self.tc else "")+("rd " if self.rd else "")+("ra " if self.ra else "")+"QUERY:%s ANSWER:%s AUTHORITY:%s ADDITIONAL:%s"%(self.qdcount,self.ancount,self.nscount,self.arcount)+" "+" ".join([str(question) for question in self.questions]))
class Query(Message):
pass
class Response(Message):
def __init__(self,query, answers=[], authorities=[], additionals=[]):
pass
#flags=bytes(2)
#flags[2]=(opcode<<3)&78
#if(qr): flags[2]|=0x80
#if(aa): flags[2]|=0x04
#if(tc): flags[2]|=0x02
#if(rd): flags[2]|=0x01
#flags[3]=rcode&0x0F
#if(ra): flags[3]|=0x80
#if(z): raise InvalidParameter("Z reserved for future use")
#self.header=pack("!HHHHHH",id,flags,len(question),len(answer),len(authority),len(additional))
##self.question=[question for question in questions]