769e7ed9 |
1 | # ldd - DNS implementation in Python |
2 | # Copyright (C) 2006 Fredrik Tolf <fredrik@dolda2000.com> |
3 | # |
4 | # This program is free software; you can redistribute it and/or modify |
5 | # it under the terms of the GNU General Public License as published by |
6 | # the Free Software Foundation; either version 2 of the License, or |
7 | # (at your option) any later version. |
8 | # |
9 | # This program is distributed in the hope that it will be useful, |
10 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
12 | # GNU General Public License for more details. |
13 | # |
14 | # You should have received a copy of the GNU General Public License |
15 | # along with this program; if not, write to the Free Software |
16 | # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
17 | |
18 | class DNNotIn(Exception): |
19 | def __init__(self, a, b): |
20 | self.a = a |
21 | self.b = b |
22 | |
23 | def __str__(self): |
24 | return str(self.a) + " not in " + str(self.b) |
25 | |
26 | class domainname: |
27 | "A class for abstract representations of domain names" |
28 | |
29 | def __init__(self, parts, rooted): |
30 | self.parts = parts |
31 | self.rooted = rooted |
32 | |
33 | def __repr__(self): |
34 | ret = "" |
35 | if len(self.parts) > 0: |
36 | for p in self.parts[:-1]: |
37 | ret = ret + p + '.' |
38 | ret = ret + self.parts[-1] |
39 | if self.rooted: |
40 | ret = ret + '.' |
41 | return ret |
42 | |
43 | def __add__(self, y): |
44 | if self.rooted: |
45 | raise Exception("cannot append to a rooted domain name") |
46 | return(domainname(self.parts + y.parts, y.rooted)) |
47 | |
48 | def __getitem__(self, y): |
49 | return domainname([self.parts[y]], self.rooted and (y == -1 or y == len(self.parts) - 1)) |
50 | |
51 | def __getslice__(self, i, j): |
52 | return domainname(self.parts[i:j], self.rooted and j >= len(self.parts)) |
53 | |
54 | def __len__(self): |
55 | return len(self.parts) |
56 | |
57 | def __eq__(self, y): |
58 | if type(y) == str: |
59 | y = fromstring(y) |
60 | if self.rooted != y.rooted: |
61 | return False |
62 | if len(self.parts) != len(y.parts): |
63 | return False |
64 | for i in range(len(self.parts)): |
65 | if self.parts[i].lower() != y.parts[i].lower(): |
66 | return False |
67 | return True |
68 | |
69 | def __ne__(self, y): |
70 | return not self.__eq__(y) |
71 | |
72 | def __contains__(self, y): |
73 | if len(self) > len(y): |
74 | return False |
75 | if len(self) == 0: |
76 | return self.rooted == y.rooted |
77 | return y[-len(self):] == self |
78 | |
79 | def __sub__(self, y): |
80 | if self not in y: |
81 | raise DNNotIn(self, y) |
82 | return self[:len(self) - len(y)] |
83 | |
84 | def __hash__(self): |
85 | ret = 0 |
86 | for part in self.parts: |
87 | ret = ret ^ hash(part) |
88 | if self.rooted: |
89 | ret = ret ^ -1 |
90 | return ret |
91 | |
92 | def canonwire(self): |
93 | ret = "" |
94 | for p in self.parts: |
95 | ret += chr(len(p)) |
96 | ret += p.lower() |
97 | ret += chr(0) |
98 | return ret |
99 | |
100 | class DNError(Exception): |
101 | emptypart = 1 |
102 | illegalchar = 2 |
103 | def __init__(self, kind): |
104 | self.kind = kind |
105 | def __str__(self): |
106 | return {1: "empty part", |
107 | 2: "illegal character"}[self.kind] |
108 | |
109 | def fromstring(name): |
110 | parts = [] |
111 | if name == ".": |
112 | return domainname([], True) |
113 | if name == "": |
114 | return domainname([], False) |
115 | while name.find('.') >= 0: |
116 | cur = name.find('.') |
117 | if cur == 0: |
118 | raise DNError(DNError.emptypart) |
119 | part = name[:cur] |
120 | for c in part: |
121 | if ord(c) < 33: |
122 | raise DNError(DNError.illegalchar) |
123 | parts.append(part) |
124 | name = name[cur + 1:] |
125 | if len(name) > 0: |
126 | parts.append(name) |
127 | rooted = False |
128 | else: |
129 | rooted = True |
130 | return domainname(parts, rooted) |
131 | |