1# Copyright (C) 2003-2007, 2009, 2010 Nominum, Inc.
2#
3# Permission to use, copy, modify, and distribute this software and its
4# documentation for any purpose with or without fee is hereby granted,
5# provided that the above copyright notice and this permission notice
6# appear in all copies.
7#
8# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
9# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
11# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
14# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15
16import cStringIO
17import struct
18
19import dns.exception
20import dns.inet
21import dns.rdata
22import dns.tokenizer
23
24class APLItem(object):
25    """An APL list item.
26
27    @ivar family: the address family (IANA address family registry)
28    @type family: int
29    @ivar negation: is this item negated?
30    @type negation: bool
31    @ivar address: the address
32    @type address: string
33    @ivar prefix: the prefix length
34    @type prefix: int
35    """
36
37    __slots__ = ['family', 'negation', 'address', 'prefix']
38
39    def __init__(self, family, negation, address, prefix):
40        self.family = family
41        self.negation = negation
42        self.address = address
43        self.prefix = prefix
44
45    def __str__(self):
46        if self.negation:
47            return "!%d:%s/%s" % (self.family, self.address, self.prefix)
48        else:
49            return "%d:%s/%s" % (self.family, self.address, self.prefix)
50
51    def to_wire(self, file):
52        if self.family == 1:
53            address = dns.inet.inet_pton(dns.inet.AF_INET, self.address)
54        elif self.family == 2:
55            address = dns.inet.inet_pton(dns.inet.AF_INET6, self.address)
56        else:
57            address = self.address.decode('hex_codec')
58        #
59        # Truncate least significant zero bytes.
60        #
61        last = 0
62        for i in xrange(len(address) - 1, -1, -1):
63            if address[i] != chr(0):
64                last = i + 1
65                break
66        address = address[0 : last]
67        l = len(address)
68        assert l < 128
69        if self.negation:
70            l |= 0x80
71        header = struct.pack('!HBB', self.family, self.prefix, l)
72        file.write(header)
73        file.write(address)
74
75class APL(dns.rdata.Rdata):
76    """APL record.
77
78    @ivar items: a list of APL items
79    @type items: list of APL_Item
80    @see: RFC 3123"""
81
82    __slots__ = ['items']
83
84    def __init__(self, rdclass, rdtype, items):
85        super(APL, self).__init__(rdclass, rdtype)
86        self.items = items
87
88    def to_text(self, origin=None, relativize=True, **kw):
89        return ' '.join(map(lambda x: str(x), self.items))
90
91    def from_text(cls, rdclass, rdtype, tok, origin = None, relativize = True):
92        items = []
93        while 1:
94            token = tok.get().unescape()
95            if token.is_eol_or_eof():
96                break
97            item = token.value
98            if item[0] == '!':
99                negation = True
100                item = item[1:]
101            else:
102                negation = False
103            (family, rest) = item.split(':', 1)
104            family = int(family)
105            (address, prefix) = rest.split('/', 1)
106            prefix = int(prefix)
107            item = APLItem(family, negation, address, prefix)
108            items.append(item)
109
110        return cls(rdclass, rdtype, items)
111
112    from_text = classmethod(from_text)
113
114    def to_wire(self, file, compress = None, origin = None):
115        for item in self.items:
116            item.to_wire(file)
117
118    def from_wire(cls, rdclass, rdtype, wire, current, rdlen, origin = None):
119        items = []
120        while 1:
121            if rdlen < 4:
122                raise dns.exception.FormError
123            header = struct.unpack('!HBB', wire[current : current + 4])
124            afdlen = header[2]
125            if afdlen > 127:
126                negation = True
127                afdlen -= 128
128            else:
129                negation = False
130            current += 4
131            rdlen -= 4
132            if rdlen < afdlen:
133                raise dns.exception.FormError
134            address = wire[current : current + afdlen]
135            l = len(address)
136            if header[0] == 1:
137                if l < 4:
138                    address += '\x00' * (4 - l)
139                address = dns.inet.inet_ntop(dns.inet.AF_INET, address)
140            elif header[0] == 2:
141                if l < 16:
142                    address += '\x00' * (16 - l)
143                address = dns.inet.inet_ntop(dns.inet.AF_INET6, address)
144            else:
145                #
146                # This isn't really right according to the RFC, but it
147                # seems better than throwing an exception
148                #
149                address = address.encode('hex_codec')
150            current += afdlen
151            rdlen -= afdlen
152            item = APLItem(header[0], negation, address, header[1])
153            items.append(item)
154            if rdlen == 0:
155                break
156        return cls(rdclass, rdtype, items)
157
158    from_wire = classmethod(from_wire)
159
160    def _cmp(self, other):
161        f = cStringIO.StringIO()
162        self.to_wire(f)
163        wire1 = f.getvalue()
164        f.seek(0)
165        f.truncate()
166        other.to_wire(f)
167        wire2 = f.getvalue()
168        f.close()
169
170        return cmp(wire1, wire2)
171