def from_packet(packet):
header = DNSHeader.from_packet(packet)
# 12 is fixed because header is always 12 octets
offset = 12
question = []
answer = []
authority = []
additional = []
for count, section, rrclass in zip([header.qdcount,
header.ancount,
header.nscount,
header.arcount],
[question,
answer,
authority,
additional],
[DNSQuestionRR,
DNSRR,
DNSRR,
DNSRR]):
for i in range(0, count):
rr, newoffset = rrclass.from_packet(packet, offset)
if isinstance(rr, DNSRR) and rr.typ == dns_type_to_int('OPT'):
rr, newoffset = DNSOptRR.from_packet(packet, offset)
offset = newoffset
section.append(rr)
return DNSMessage(header,
question,
answer,
authority,
additional)
def canonical_l1(self, ttl):
rdata = bytearray()
for part in self.address.split('.'):
rdata.append(int(part))
return DNSRR(self.name.lower(),
dns_type_to_int(self.typ),
dns_class_to_int('IN'),
ttl,
4,
rdata,
None,
None)
def canonical_l1(self, ttl):
rdata = bytearray()
rdata.extend(pack('! H B B',
self.keytag,
dnssec_algorithm_to_int(self.algorithm),
dnssec_digest_type_to_int(self.digest_type)))
rdata.extend(self.digest)
return DNSRR(self.name.lower(),
dns_type_to_int(self.typ),
dns_class_to_int('IN'),
ttl,
len(rdata),
rdata,
None,
None)
def canonical_l1(self, ttl):
rdata = bytearray()
rdata.extend(pack('! H B B',
self.flags,
3,
dnssec_algorithm_to_int(self.algorithm)))
rdata.extend(self.public_key)
return DNSRR(self.name.lower(),
dns_type_to_int(self.typ),
dns_class_to_int('IN'),
ttl,
len(rdata),
rdata,
None,
None)
def to_rr(self):
b = bytearray()
b.extend(pack('! H B B',
self.keytag,
dnssec_algorithm_to_int(self.algorithm),
dnssec_digest_type_to_int(self.digest_type)))
b.extend(self.digest)
return DNSRR(self.name,
dns_type_to_int(self.typ),
dns_class_to_int(self.clas),
self.ttl,
len(b),
b,
None,
None)
def canonical_l1(self, ttl):
rdata = bytearray()
rdata.extend(encode_name(self.mname))
rdata.extend(encode_name(self.rname))
rdata.extend(pack('! I I I I I',
self.serial,
self.refresh,
self.retry,
self.expire,
self.minimum))
return DNSRR(self.name.lower(),
dns_type_to_int(self.typ),
dns_class_to_int('IN'),
ttl,
len(rdata),
rdata,
None,
None)
def make_query_message(qname,
qtype,
qclass,
rd,
cd,
udp_payload_size,
dnssec_ok=False):
msgid = random_dns_message_id()
qrr = DNSQuestionRR(qname, dns_type_to_int(qtype),
dns_class_to_int(qclass))
if udp_payload_size is not None:
opt_rr = DNSOptRR(udp_payload_size, 0, 0, dnssec_ok, [])
else:
opt_rr = None
dns_message = DNSMessage(
DNSHeader(msgid,
DNSFlags(False, 0, False, False, rd, False, False, cd, 0), 1,
0, 0, 1 if opt_rr else 0), [qrr], [], [],
[opt_rr] if opt_rr is not None else [])
return dns_message