Class: Scriptroute::NTP

Inherits:
UDP show all
Defined in:
lib/scriptroute/packets.rb

Constant Summary

Constants inherited from IPv4

IPv4::IPPROTO_ICMP, IPv4::IPPROTO_TCP, IPv4::IPPROTO_UDP

Instance Attribute Summary collapse

Attributes inherited from UDP

#uh_dport, #uh_sport, #uh_sum, #uh_ulen

Attributes inherited from IPv4

#ip_dst, #ip_hl, #ip_id, #ip_len, #ip_off, #ip_options, #ip_p, #ip_src, #ip_sum, #ip_tos, #ip_ttl, #ip_v

Instance Method Summary collapse

Methods inherited from UDP

#ip_payload_len, #to_s, #udp_unmarshal

Methods inherited from IPv4

#add_option, #calculate_header_len, #calculate_packet_len, creator, #ip_payload_len, #ipv4_unmarshal, #to_s

Constructor Details

#initialize(paylen_or_str = 0) ⇒ NTP

Returns a new instance of NTP.



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# File 'lib/scriptroute/packets.rb', line 677

def initialize(paylen_or_str = 0)
  if(paylen_or_str.is_a?(Fixnum)) then
    if( paylen_or_str < 0) then raise "payload length must be >= 0" end
    
    @leap_indicator = 3 # alarm condition / clock not synchronized
    @version_number = 4 # unclear if it should be.
    @mode = 3 # client
    @stratum = 0 # unspecified
    @poll_interval = 4 # 16s
    @precision = -6 # emulate ntpdate, though -20 is more likely
    @root_delay = 1.0 # packed funny.
    @root_dispersion = 1.0 # packed funny.
    @reference_identifier = '0.0.0.0'
    @reference_timestamp = 0.0
    @originate_timestamp = 0.0
    @receive_timestamp = 0.0
    @transmit_timestamp = 0.0
    
    super( paylen_or_str + 48 )
    
    @uh_dport = 123
    
  else
    ntp_unmarshal(paylen_or_str)
  end
end

Instance Attribute Details

#leap_indicator ⇒ Fixnum

Returns:

  • (Fixnum) 


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# File 'lib/scriptroute/packets.rb', line 671

def leap_indicator
  @leap_indicator
end

#mode ⇒ Fixnum

Returns:

  • (Fixnum) 


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# File 'lib/scriptroute/packets.rb', line 671

def mode
  @mode
end

#originate_timestamp ⇒ Object

Returns the value of attribute originate_timestamp.



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# File 'lib/scriptroute/packets.rb', line 674

def originate_timestamp
  @originate_timestamp
end

#poll_interval ⇒ Object

Returns the value of attribute poll_interval.



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# File 'lib/scriptroute/packets.rb', line 672

def poll_interval
  @poll_interval
end

#precision ⇒ Object

Returns the value of attribute precision.



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# File 'lib/scriptroute/packets.rb', line 672

def precision
  @precision
end

#receive_timestamp ⇒ Object

Returns the value of attribute receive_timestamp.



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# File 'lib/scriptroute/packets.rb', line 675

def receive_timestamp
  @receive_timestamp
end

#reference_identifier ⇒ Object

Returns the value of attribute reference_identifier.



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# File 'lib/scriptroute/packets.rb', line 673

def reference_identifier
  @reference_identifier
end

#reference_timestamp ⇒ Object

Returns the value of attribute reference_timestamp.



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# File 'lib/scriptroute/packets.rb', line 674

def reference_timestamp
  @reference_timestamp
end

#root_delay ⇒ Object

Returns the value of attribute root_delay.



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# File 'lib/scriptroute/packets.rb', line 672

def root_delay
  @root_delay
end

#root_dispersion ⇒ Object

Returns the value of attribute root_dispersion.



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# File 'lib/scriptroute/packets.rb', line 673

def root_dispersion
  @root_dispersion
end

#stratum ⇒ Fixnum

Returns:

  • (Fixnum) 


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# File 'lib/scriptroute/packets.rb', line 671

def stratum
  @stratum
end

#transmit_timestamp ⇒ Object

Returns the value of attribute transmit_timestamp.



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# File 'lib/scriptroute/packets.rb', line 675

def transmit_timestamp
  @transmit_timestamp
end

#version_number ⇒ Fixnum

Returns:

  • (Fixnum) 


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# File 'lib/scriptroute/packets.rb', line 671

def version_number
  @version_number
end

Instance Method Details

#float_to_two_longs(flt) ⇒ Object 



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# File 'lib/scriptroute/packets.rb', line 740

def float_to_two_longs(flt)
  flt == nil and raise "need a float"
  [ flt.to_i, ((flt - flt.to_i) * 4294967296).to_i ]
end

#float_to_two_shorts(flt) ⇒ Object 



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# File 'lib/scriptroute/packets.rb', line 735

def float_to_two_shorts(flt)
  flt == nil and raise "need a float"
  [ flt.to_i, ((flt - flt.to_i) * 65536).to_i ]
end

#marshal ⇒ String

Returns The packet in string form.

Returns:

  • (String) —

    The packet in string form



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# File 'lib/scriptroute/packets.rb', line 756

def marshal
  if ($VERBOSE) then
    puts "marshaling with IP payload length %d" % ip_payload_len 
  end
  super + [ @leap_indicator * 64 + @version_number * 8 + @mode, @stratum, @poll_interval, @precision, 
    float_to_two_shorts(@root_delay),
    float_to_two_shorts(@root_dispersion),
    @reference_identifier.to_i, 
    float_to_two_longs(@reference_timestamp),
    float_to_two_longs(@originate_timestamp),
    float_to_two_longs(@receive_timestamp),
    float_to_two_longs(@transmit_timestamp) ].flatten.pack("cccc" +
    "nn" +
    "nn" +
    "N" +
    "NN" +
    "NN" +
    "NN" +
    "NN") + "\0" * ( @uh_ulen - 8 - 48 )
  
end

#ntp_unmarshal(str) ⇒ Object 



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# File 'lib/scriptroute/packets.rb', line 704

def ntp_unmarshal(str)

  ntp_lvm, @stratum, @poll_interval, @precision,
    root_delay1,root_delay2,
    root_dispersion1,root_dispersion2,
    r1,r2,r3,r4,
    reference_timestamp1,reference_timestamp2,
    originate_timestamp1,originate_timestamp2,
    receive_timestamp1,receive_timestamp2,
    transmit_timestamp1, transmit_timestamp2 = str.unpack( "cccc" +
    "nn" +
    "nn" +
    "cccc" +
    "NN" +
    "NN" +
    "NN" +
    "NN");

  @leap_indicator = (ntp_lvm >> 6) & 0xfc
  @version_number = (ntp_lvm & 0x38) >> 3
  @mode = ntp_lvm & 0x07
  @root_delay = root_delay1+root_delay2/65536.0
  @root_dispersion = root_dispersion1+root_dispersion2/65536.0
  @reference_identifier = "%d.%d.%d.%d"% [r1,r2,r3,r4].map{ |i| (i<0)?i+256:i }
  @reference_timestamp = reference_timestamp1 + 0.0 + reference_timestamp2/4294967296.0
  @originate_timestamp = originate_timestamp1 + originate_timestamp2/4294967296.0
  @receive_timestamp = receive_timestamp1 + receive_timestamp2/4294967296.0
  @transmit_timestamp = transmit_timestamp1 + transmit_timestamp2/4294967296.0
  
end

#to_bits(int, bits) ⇒ Object 



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# File 'lib/scriptroute/packets.rb', line 745

def to_bits(int, bits)
  ret = ""
  (1..bits).each do |b|
    ret += (int % 2).to_s
    int =  int / 2
  end
  ret
end