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(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 run(self):
global taskQueue, stopFlag, work_treads_list
while True:
if stopFlag:
print("RecvThread Ended")
break
rlist, _, _ = select.select([self.m_socket], [], [], 1)
if len(rlist) != 0:
print("Received {} packets".format(len(rlist)))
for tempSocket in rlist:
try:
data, addr = tempSocket.recvfrom(1024)
recvTimestamp = ntp_packet.system_to_ntp_time(
time.time())
taskQueue.put((data, addr, recvTimestamp))
workThread = WorkThread(self.m_socket, self.lie_offset)
work_treads_list.append(workThread)
workThread.start()
except socket.error as msg:
print(msg)
