| 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 | |