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
