Source code for dns.rdtypes.IN.APL

# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license

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import binascii
import codecs
import struct

import dns.exception
import dns.immutable
import dns.ipv4
import dns.ipv6
import dns.rdata
import dns.tokenizer


[docs] @dns.immutable.immutable class APLItem: """An APL list item.""" __slots__ = ["family", "negation", "address", "prefix"] def __init__(self, family, negation, address, prefix): self.family = dns.rdata.Rdata._as_uint16(family) self.negation = dns.rdata.Rdata._as_bool(negation) if self.family == 1: self.address = dns.rdata.Rdata._as_ipv4_address(address) self.prefix = dns.rdata.Rdata._as_int(prefix, 0, 32) elif self.family == 2: self.address = dns.rdata.Rdata._as_ipv6_address(address) self.prefix = dns.rdata.Rdata._as_int(prefix, 0, 128) else: self.address = dns.rdata.Rdata._as_bytes(address, max_length=127) self.prefix = dns.rdata.Rdata._as_uint8(prefix) def __str__(self): if self.negation: return "!%d:%s/%s" % (self.family, self.address, self.prefix) else: return "%d:%s/%s" % (self.family, self.address, self.prefix) def to_wire(self, file): if self.family == 1: address = dns.ipv4.inet_aton(self.address) elif self.family == 2: address = dns.ipv6.inet_aton(self.address) else: address = binascii.unhexlify(self.address) # # Truncate least significant zero bytes. # last = 0 for i in range(len(address) - 1, -1, -1): if address[i] != 0: last = i + 1 break address = address[0:last] l = len(address) assert l < 128 if self.negation: l |= 0x80 header = struct.pack("!HBB", self.family, self.prefix, l) file.write(header) file.write(address)
[docs] @dns.immutable.immutable class APL(dns.rdata.Rdata): """APL record.""" # see: RFC 3123 __slots__ = ["items"] def __init__(self, rdclass, rdtype, items): super().__init__(rdclass, rdtype) for item in items: if not isinstance(item, APLItem): raise ValueError("item not an APLItem") self.items = tuple(items)
[docs] def to_text(self, origin=None, relativize=True, **kw): return " ".join(map(str, self.items))
@classmethod def from_text( cls, rdclass, rdtype, tok, origin=None, relativize=True, relativize_to=None ): items = [] for token in tok.get_remaining(): item = token.unescape().value if item[0] == "!": negation = True item = item[1:] else: negation = False (family, rest) = item.split(":", 1) family = int(family) (address, prefix) = rest.split("/", 1) prefix = int(prefix) item = APLItem(family, negation, address, prefix) items.append(item) return cls(rdclass, rdtype, items) def _to_wire(self, file, compress=None, origin=None, canonicalize=False): for item in self.items: item.to_wire(file) @classmethod def from_wire_parser(cls, rdclass, rdtype, parser, origin=None): items = [] while parser.remaining() > 0: header = parser.get_struct("!HBB") afdlen = header[2] if afdlen > 127: negation = True afdlen -= 128 else: negation = False address = parser.get_bytes(afdlen) l = len(address) if header[0] == 1: if l < 4: address += b"\x00" * (4 - l) elif header[0] == 2: if l < 16: address += b"\x00" * (16 - l) else: # # This isn't really right according to the RFC, but it # seems better than throwing an exception # address = codecs.encode(address, "hex_codec") item = APLItem(header[0], negation, address, header[1]) items.append(item) return cls(rdclass, rdtype, items)