def from_bytes(cls, packet, offset, rdlength):
"""Create a RecordData object from bytes.
Args:
packet (bytes): packet.
offset (int): offset in message.
rdlength (int): length of rdata.
"""
mname, offset = Name.from_bytes(packet, offset)
rname, offset = Name.from_bytes(packet, offset)
serial = struct.unpack_from("!I", packet, offset)[0]
refresh = struct.unpack_from("!i", packet, offset + 4)[0]
retry = struct.unpack_from("!i", packet, offset + 8)[0]
expire = struct.unpack_from("!i", packet, offset + 12)[0]
minimum = struct.unpack_from("!I", packet, offset + 16)[0]
return cls(mname, rname, serial, refresh, retry, expire, minimum), offset + 20
def from_bytes(cls, packet, offset):
"""Convert ResourceRecord from bytes."""
name, offset = Name.from_bytes(packet, offset)
type_ = Type(struct.unpack_from("!H", packet, offset)[0])
class_ = Class(struct.unpack_from("!H", packet, offset + 2)[0])
ttl, rdlength = struct.unpack_from("!iH", packet, offset + 4)
offset += 10
rdata = RecordData.create_from_bytes(type_, packet, offset, rdlength)
offset += rdlength
return cls(name, type_, class_, ttl, rdata), offset
def from_bytes(cls, packet, offset, rdlength):
"""Create a RecordData object from bytes.
Args:
packet (bytes): packet.
offset (int): offset in message.
rdlength (int): length of rdata.
"""
nsdname, offset = Name.from_bytes(packet, offset)
return cls(nsdname)
def test_name_from_bytes1(self):
packet = b"\x03www\x07example\x03com\x00"
name1, offset = Name.from_bytes(packet, 0)
name2 = Name("www.example.com")
self.assertEqual(offset, 17)
self.assertEqual(name1, name2)
def test_name_from_bytes4(self):
packet = b"\x00"
name, offset = Name.from_bytes(packet, 0)
self.assertEqual(name.labels, [])
def test_name_from_bytes3(self):
packet = b"\x41" + b"a" * 65
with self.assertRaises(ValueError):
Name.from_bytes(packet, 0)
def test_name_from_bytes2(self):
packet = b"\x03www\x07example\x03com\x00\x03ftp\xc0\x04"
name1, offset = Name.from_bytes(packet, 0)
name2, offset = Name.from_bytes(packet, offset)
self.assertEqual(name1, Name("www.example.com"))
self.assertEqual(name2, Name("ftp.example.com"))
def from_bytes(cls, packet, offset):
"""Convert Question from bytes."""
qname, offset = Name.from_bytes(packet, offset)
qtype = Type(struct.unpack_from("!H", packet, offset)[0])
qclass = Class(struct.unpack_from("!H", packet, offset + 2)[0])
return cls(qname, qtype, qclass), offset + 4
from dns.resource import ResourceRecord, NSRecordData, ARecordData
from dns.name import Name
from dns.types import Type
from dns.classes import Class
b = Name('a.').to_bytes(0)
x, y = Name.from_bytes(b, 0)
print(b, x)
b = Name('b.').to_bytes(0)
x, y = Name.from_bytes(b, 0)
print(b, x)
b = Name('.').to_bytes(0)
x, y = Name.from_bytes(b, 0)
print(b, x)