Class: NET::NTP

Inherits:
Object
  • Object
show all
Defined in:
lib/ntp.rb

Constant Summary collapse

VERSION =

:nodoc:

'1.0.0'
TIMEOUT =

:nodoc:

60
NTP_ADJ =

:nodoc:

2208988800
MODE = 
{
0    =>    'reserved',
1    =>    'symmetric active',
2    =>    'symmetric passive',
3    =>    'client',
4    =>    'server',
5    =>    'broadcast',
6    =>    'reserved for NTP control message',
7    =>    'reserved for private use' }
STRATUM = 
{
0    =>    'unspecified or unavailable',
1    =>    'primary reference (e.g., radio clock)' }
STRATUM_ONE_TEXT = 
{
'LOCL'  => 'uncalibrated local clock used as a primary reference for a subnet without external means of synchronization',
'PPS'   => 'atomic clock or other pulse-per-second source individually calibrated to national standards',
'ACTS'  => 'NIST dialup modem service',
'USNO'  => 'USNO modem service',
'PTB'   => 'PTB (Germany) modem service',
'TDF'   => 'Allouis (France) Radio 164 kHz',
'DCF'   => 'Mainflingen (Germany) Radio 77.5 kHz',
'MSF'   => 'Rugby (UK) Radio 60 kHz',
'WWV'   => 'Ft. Collins (US) Radio 2.5, 5, 10, 15, 20 MHz',
'WWVB'  => 'Boulder (US) Radio 60 kHz',
'WWVH'  => 'Kaui Hawaii (US) Radio 2.5, 5, 10, 15 MHz',
'CHU'   => 'Ottawa (Canada) Radio 3330, 7335, 14670 kHz',
'LORC'  => 'LORAN-C radionavigation system',
'OMEG'  => 'OMEGA radionavigation system',
'GPS'   => 'Global Positioning Service',
'GOES'  => 'Geostationary Orbit Environment Satellite' }
LEAP_INDICATOR = 
{
0    =>     'no warning',
1    =>     'last minute has 61 seconds',
2    =>     'last minute has 59 seconds)',
3    =>     'alarm condition (clock not synchronized)' }

Class Method Summary collapse

Class Method Details

.get_ntp_response(host = "pool.ntp.org", port = "ntp") ⇒ Object

Sends an NTP datagram to the specified NTP server and returns a hash based upon RFC1305 and RFC2030.



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# File 'lib/ntp.rb', line 96

def NTP.get_ntp_response(host="pool.ntp.org", port="ntp")

  sock = UDPSocket.new
  sock.connect(host, port)

  client_time_send = Time.new.to_i
  client_localtime = client_time_send
  client_adj_localtime = client_localtime + NTP_ADJ
  client_frac_localtime = frac2bin(client_adj_localtime)
  
  ntp_msg =
    (['00011011']+Array.new(12, 0)+[client_localtime, client_frac_localtime.to_s]).pack("B8 C3 N10 B32")
  
  sock.print ntp_msg
  sock.flush
 
  data=NIL 
  Timeout::timeout(TIMEOUT) do |t|
    data=sock.recvfrom(960)[0]
  end
  client_time_receive = Time.new.to_i
  
  ntp_fields = %w{ byte1 stratum poll precision
   delay delay_fb disp disp_fb ident
   ref_time ref_time_fb
   org_time org_time_fb
   recv_time recv_time_fb
   trans_time trans_time_fb }
  
  packetdata =
      data.unpack("a C3   n B16 n B16 H8   N B32 N B32   N B32 N B32"); 
  
  tmp_pkt=Hash.new
  ntp_fields.each do |f|
    tmp_pkt[f]=packetdata.shift
  end

  packet=Hash.new
  packet['Leap Indicator']=(tmp_pkt['byte1'][0] & 0xC0) >> 6 
  packet['Version Number']=(tmp_pkt['byte1'][0] & 0x38) >> 3
  packet['Mode']=(tmp_pkt['byte1'][0] & 0x07)
  packet['Stratum']=tmp_pkt['stratum']
  packet['Poll Interval']=tmp_pkt['poll']
  packet['Precision']=tmp_pkt['precision'] - 255
  packet['Root Delay']=bin2frac(tmp_pkt['delay_fb'])
  packet['Root Dispersion']=tmp_pkt['disp']
  packet['Reference Clock Identifier']=unpack_ip(tmp_pkt['stratum'], tmp_pkt['ident'])
  packet['Reference Timestamp']=((tmp_pkt['ref_time'] + bin2frac(tmp_pkt['ref_time_fb'])) - NTP_ADJ)
  packet['Originate Timestamp']=((tmp_pkt['org_time'] + bin2frac(tmp_pkt['org_time_fb'])) )
  packet['Receive Timestamp']=((tmp_pkt['recv_time'] + bin2frac(tmp_pkt['recv_time_fb'])) - NTP_ADJ)
  packet['Transmit Timestamp']=((tmp_pkt['trans_time'] + bin2frac(tmp_pkt['trans_time_fb'])) - NTP_ADJ)
  
  return packet

end