| # Copyright (C) 2001-2007, 2009, 2010 Nominum, Inc. |
| # |
| # Permission to use, copy, modify, and distribute this software and its |
| # documentation for any purpose with or without fee is hereby granted, |
| # provided that the above copyright notice and this permission notice |
| # appear in all copies. |
| # |
| # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES |
| # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR |
| # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
| # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT |
| # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
| |
| """DNS Message Flags.""" |
| |
| # Standard DNS flags |
| |
| QR = 0x8000 |
| AA = 0x0400 |
| TC = 0x0200 |
| RD = 0x0100 |
| RA = 0x0080 |
| AD = 0x0020 |
| CD = 0x0010 |
| |
| # EDNS flags |
| |
| DO = 0x8000 |
| |
| _by_text = { |
| 'QR' : QR, |
| 'AA' : AA, |
| 'TC' : TC, |
| 'RD' : RD, |
| 'RA' : RA, |
| 'AD' : AD, |
| 'CD' : CD |
| } |
| |
| _edns_by_text = { |
| 'DO' : DO |
| } |
| |
| |
| # We construct the inverse mappings programmatically to ensure that we |
| # cannot make any mistakes (e.g. omissions, cut-and-paste errors) that |
| # would cause the mappings not to be true inverses. |
| |
| _by_value = dict([(y, x) for x, y in _by_text.iteritems()]) |
| |
| _edns_by_value = dict([(y, x) for x, y in _edns_by_text.iteritems()]) |
| |
| def _order_flags(table): |
| order = list(table.iteritems()) |
| order.sort() |
| order.reverse() |
| return order |
| |
| _flags_order = _order_flags(_by_value) |
| |
| _edns_flags_order = _order_flags(_edns_by_value) |
| |
| def _from_text(text, table): |
| flags = 0 |
| tokens = text.split() |
| for t in tokens: |
| flags = flags | table[t.upper()] |
| return flags |
| |
| def _to_text(flags, table, order): |
| text_flags = [] |
| for k, v in order: |
| if flags & k != 0: |
| text_flags.append(v) |
| return ' '.join(text_flags) |
| |
| def from_text(text): |
| """Convert a space-separated list of flag text values into a flags |
| value. |
| @rtype: int""" |
| |
| return _from_text(text, _by_text) |
| |
| def to_text(flags): |
| """Convert a flags value into a space-separated list of flag text |
| values. |
| @rtype: string""" |
| |
| return _to_text(flags, _by_value, _flags_order) |
| |
| |
| def edns_from_text(text): |
| """Convert a space-separated list of EDNS flag text values into a EDNS |
| flags value. |
| @rtype: int""" |
| |
| return _from_text(text, _edns_by_text) |
| |
| def edns_to_text(flags): |
| """Convert an EDNS flags value into a space-separated list of EDNS flag |
| text values. |
| @rtype: string""" |
| |
| return _to_text(flags, _edns_by_value, _edns_flags_order) |
