def run(self):
global taskQueue, stopFlag
while True:
if stopFlag:
print("WorkThread Ended")
break
try:
data, addr, recvTimestamp = taskQueue.get(timeout=1)
recvPacket = NTPPacket()
recvPacket.from_data(data)
# Server mode - 4 and SNTP v4
sendPacket = NTPPacket(version=4, mode=4)
# According to rfc4330 most fields == 0
# it is already set in NTPPacket constructor
# Timestamp Name ID When Generated
# ------------------------------------------------------------
# Originate Timestamp T1 time request sent by client
# Receive Timestamp T2 time request received by server
# Transmit Timestamp T3 time reply sent by server
# Destination Timestamp T4 time reply received by client
timeStamp_high, timeStamp_low = recvPacket.GetTxTimeStamp()
sendPacket.SetOriginTimeStamp(timeStamp_high, timeStamp_low)
# Simulate that we have different time on server
sendPacket.recv_timestamp = recvTimestamp - self.lie_offset
sendPacket.tx_timestamp = ntp_packet.system_to_ntp_time(
time.time() - self.lie_offset)
# Dummy info to be a correct sntp packet
sendPacket.stratum = 2
sendPacket.ref_timestamp = recvTimestamp - 5
sendPacket.poll = 10
# sendPacket.precision = 2
# sendPacket.root_delay = 1
# sendPacket.root_dispersion = 1
# sendPacket.ref_id = 1809582983 # ip 107.220.11.135
# sendPacket = b"\x24\x02\x03\xee\x00\x00\x00\x37\x00\x00\x05\x0f\x6b\xdc\x0b\x87\xd8\xe7\x2f\xa6\x1a\xb4\xc9\x72\xd8\xe7\x30\x27\x66\x15\xdb\x33\xd8\xe7\x30\x26\x02\xe6\xcb\x21\xd8\xe7\x30\x26\x02\xeb\x94\xac"
self.m_socket.sendto(sendPacket.to_data(), addr)
print("Sended to {}:{}".format(addr[0], addr[1]))
except Empty:
continue
def _internal_send_packet(server, port, version, packet=None):
if not packet:
packet = NTPPacket(transmit=time.time() + NTPClient.FORMAT_DIFF)
answer = NTPPacket(version_number=version)
with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as s:
s.settimeout(NTPClient.WAITING_TIME)
s.sendto(packet.pack(), (server, port))
data = s.recv(48)
arrive_time = time.time() + NTPClient.FORMAT_DIFF
answer.unpack(data)
return answer, arrive_time
def request(self, host, version=4, port='ntp', timeout=5):
"""
Query a SNTP server.
:param host: server name/address
:param version: SNTP version to use
:param port: server port
:param timeout: timeout on socket operations
:returns: NTPStats object
"""
# lookup server address
addrinfo = socket.getaddrinfo(host, port)[0]
sockaddr = addrinfo[4]
# create the socket
# print(sockaddr)
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
try:
s.settimeout(timeout)
# create the request packet - mode 3 is client
query_packet = NTPPacket(mode=3, version=version,
tx_timestamp=ntp_packet.system_to_ntp_time(time.time()))
# send the request
s.sendto(query_packet.to_data(), sockaddr)
# wait for the response - check the source address
src_addr = None,
while src_addr[0] != sockaddr[0]:
response_packet, src_addr = s.recvfrom(256)
# build the destination timestamp
dest_timestamp = ntp_packet.system_to_ntp_time(time.time())
except socket.timeout:
raise NTPException("No response received from %s." % host)
finally:
s.close()
# construct corresponding packet
sntp_packet = NTPPacket()
sntp_packet.from_data(response_packet)
sntp_packet.dest_timestamp = dest_timestamp
print("Offset: ", (((sntp_packet.recv_timestamp - sntp_packet.orig_timestamp) +
(sntp_packet.tx_timestamp - sntp_packet.dest_timestamp)) / 2))
print("Round trip: ", ((sntp_packet.dest_timestamp - sntp_packet.orig_timestamp) -
(sntp_packet.tx_timestamp - sntp_packet.recv_timestamp)))
return sntp_packet
def run_server(delay, port):
with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
try:
sock.bind(("127.0.0.1", port))
except Exception:
print("Can not create server (sure port is free)")
return
while True:
data, address = sock.recvfrom(1024)
print("Connected: ", address)
try:
packet = NTPPacket().unpack(data)
except UnpackError:
print("Wrong packet format")
sock.sendto(b"Wrong packet format", address)
continue
thread = threading.Thread(target=handle_connection,
args=(packet, sock, address, delay))
thread.start()
def fake_server(address):
s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind( (address, 123) )
drift_start = time.time()
speed = 0.9996
while True:
packet, source = s.recvfrom(100)
print('Received {length} byte packet from {source}'.format(length=len(packet), source=source[0]))
packet = NTPPacket.from_bytes(packet)
if packet.version not in (3, 4):
print('Unsupported NTP version.')
continue
if packet.mode != 3:
print('Not a client request.')
continue
try:
print('Client time:', packet.transmit_timestamp)
except:
pass
time_since_start = time.time() - drift_start
return_time = drift_start + time_since_start * speed
response = NTPPacket()
response.version = packet.version
response.mode = 4
response.stratum = 1
response.reference_identifier = b'XFAK'
response.origin_timestamp = packet.transmit_timestamp
response.reference_timestamp = NTPTimestamp.from_unix_timestamp(return_time)
response.receive_timestamp = NTPTimestamp.from_unix_timestamp(return_time)
response.transmit_timestamp = NTPTimestamp.from_unix_timestamp(return_time)
response = response.to_bytes()
s.sendto(response, source)
