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16 """DNS Message Flags."""
17
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20 QR = 0x8000
21 AA = 0x0400
22 TC = 0x0200
23 RD = 0x0100
24 RA = 0x0080
25 AD = 0x0020
26 CD = 0x0010
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30 DO = 0x8000
31
32 _by_text = {
33 'QR' : QR,
34 'AA' : AA,
35 'TC' : TC,
36 'RD' : RD,
37 'RA' : RA,
38 'AD' : AD,
39 'CD' : CD
40 }
41
42 _edns_by_text = {
43 'DO' : DO
44 }
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49
50
51 _by_value = dict([(y, x) for x, y in _by_text.items()])
52
53 _edns_by_value = dict([(y, x) for x, y in _edns_by_text.items()])
54
56 return sorted(table.items(), reverse=True)
57
58 _flags_order = _order_flags(_by_value)
59
60 _edns_flags_order = _order_flags(_edns_by_value)
61
62 -def _from_text(text, table):
63 flags = 0
64 tokens = text.split()
65 for t in tokens:
66 flags = flags | table[t.upper()]
67 return flags
68
69 -def _to_text(flags, table, order):
70 text_flags = []
71 for k, v in order:
72 if flags & k != 0:
73 text_flags.append(v)
74 return ' '.join(text_flags)
75
77 """Convert a space-separated list of flag text values into a flags
78 value.
79 @rtype: int"""
80
81 return _from_text(text, _by_text)
82
84 """Convert a flags value into a space-separated list of flag text
85 values.
86 @rtype: string"""
87
88 return _to_text(flags, _by_value, _flags_order)
89
90
92 """Convert a space-separated list of EDNS flag text values into a EDNS
93 flags value.
94 @rtype: int"""
95
96 return _from_text(text, _edns_by_text)
97
98 -def edns_to_text(flags):
99 """Convert an EDNS flags value into a space-separated list of EDNS flag
100 text values.
101 @rtype: string"""
102
103 return _to_text(flags, _edns_by_value, _edns_flags_order)
104