def encode_message(self):
message = b''
message += self.header.encode_header()
question = DNSQuestion(self.q_type, self.host_name)
message += question.encode_question()
return message
def test_question_data(self):
data = b'\x06yandex\x02ru\x00\x00\x1c\x00\x01\xc0\x0c\x00' \
b'\x1c\x00\x01\x00\x00\x00C\x00\x10*\x02\x06\xb8\x00' \
b'\n\x00\x00\x00\x00\x00\x00\x00\x00\x00\n'
question = DNSQuestion(is_IPv6=True, host_name='')
question.decode_question(data, 0)
self.assertEqual('yandex.ru', question.host_name)
self.assertEqual(28, question.type)
self.assertEqual(1, question.request_class)
def encode_message(self, is_TCP):
message = b''
message += self.header.encode_header()
question = DNSQuestion(self.q_type, self.host_name)
message += question.encode_question()
if is_TCP:
message = struct.pack('!H', len(message)) + message
return message
def __init__(self, message, offset):
data = DNSQuestion.decode_domain_name(message, offset)
self.primary_name_server = data[0]
offset = data[1]
data = DNSQuestion.decode_domain_name(message, offset)
self.authority_mailbox = data[0]
offset = data[1]
self.serial_number = str(
struct.unpack('!I', message[offset:offset + 4])[0])
offset += 4
self.refresh_interval = str(
struct.unpack('!I', message[offset:offset + 4])[0])
offset += 4
self.retry_interval = struct.unpack('!I',
message[offset:offset + 4])[0]
offset += 4
self.expire_limit = struct.unpack('!I', message[offset:offset + 4])[0]
offset += 4
self.minimum_TTL = struct.unpack('!I', message[offset:offset + 4])[0]
def decode_info(self, message, offset):
name_offset = struct.unpack_from('!H', message, offset)[0] & 0x1fff
self.host_name = DNSQuestion.decode_domain_name(message,
name_offset)[0]
offset += 2
self.type = struct.unpack('!H', message[offset:offset + 2])[0]
offset += 2
self.request_class = struct.unpack('!H', message[offset:offset + 2])[0]
offset += 2
self.ttl = struct.unpack('!I', message[offset:offset + 4])[0]
offset += 4
self.data_length = struct.unpack('!H', message[offset:offset + 2])[0]
offset += 2
for i in range(self.data_length):
self.address += str(
struct.unpack_from('!B', message, offset + i)[0]) + '.'
self.address = self.address[:-1]
self.request = Request(self.data_length, self.type, message, offset)
return offset + self.data_length
def decode_message(self, message):
self.header.decode_header(message)
offset = self.header.length
for i in range(self.header.questions_count):
self.questions.append(DNSQuestion(self.q_type, self.host_name))
offset = self.questions[i].decode_question(message, offset)
for i in range(self.header.answers_count):
self.answers.append(Answer())
offset = self.answers[i].decode_info(message, offset)
for i in range(self.header.access_rights_count):
self.authority_rrs.append(Answer())
offset = self.authority_rrs[i].decode_info(message, offset)
for i in range(self.header.additional_info_count):
self.additional_rrs.append(Answer())
offset = self.additional_rrs[i].decode_info(message, offset)
def start_working(self):
with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
sock.settimeout(15)
sock.bind((self.server_ip, 1024))
with open(self.cache_file, 'rb') as f:
self.cache = pickle.load(f)
while True:
try:
data, self.client_ip = sock.recvfrom(1024)
print('Пакет получен!')
# раскодировать пакет и достать имя и тип запроса
hostname, q_type = DNSQuestion.decode_s_question(data, 12)
# если лежит в кэше
current_time = int(time.time())
if self.is_exist_in_cache(q_type, hostname) and self.cache[q_type][hostname][1] >= current_time:
print('In if!')
# to take data from cache
print(self.cache[q_type][hostname])
sock.sendto(self.cache[q_type][hostname][0], self.client_ip)
print('Пакет отправлен!\n')
elif self.is_exist_in_cache(q_type, hostname) and self.cache[q_type][hostname][1] < current_time:
self.cache[q_type].pop(hostname)
print('In else!')
data_from_dns = self.ask_to_dns(q_type, hostname)
sock.sendto(data_from_dns, self.client_ip)
print('Пакет отправлен!\n')
else:
print('In else!')
data_from_dns = self.ask_to_dns(q_type, hostname)
sock.sendto(data_from_dns, self.client_ip)
print('Пакет отправлен!\n')
except socket.timeout or KeyboardInterrupt:
with open(self.cache_file, 'wb') as f:
pickle.dump(self.cache, f)
break
def __init__(self, message, offset):
self.name_server = DNSQuestion.decode_domain_name(message, offset)[0]
def __init__(self, message, offset):
self.priority = struct.unpack('!H', message[offset:offset + 2])[0]
offset += 2
self.mail_exchanger = DNSQuestion.decode_domain_name(
message, offset + 2)[0]
def __init__(self, message, offset):
self.mailbox = DNSQuestion.decode_domain_name(message, offset)[0]
def __init__(self, message, offset):
self.name = DNSQuestion.decode_domain_name(message, offset)[0]
print(' PTR: {0}'.format(self.name))
exit(0)