Class: PacketGen::PcapNG::EPB

Inherits:
Block
  • Object
show all
Defined in:
lib/packetgen/pcapng/epb.rb

Overview

EPB represents a Enhanced Packet Block (EPB) of a pcapng file.

EPB Definition

Int32   :type           Default: 0x00000006
Int32   :block_len
Int32   :interface_id
Int32   :tsh (timestamp high)
Int32   :tsl (timestamp low)
Int32   :cap_len
Int32   :orig_len
String  :data
String  :options
Int32   :block_len2

Author:

  • Sylvain Daubert

Constant Summary collapse

MIN_SIZE =

Minimum EPB size

8 * 4

Instance Attribute Summary collapse

Attributes inherited from Block

#block_len, #block_len2, #type

Instance Method Summary collapse

Methods inherited from Block

#options?, #pad_field, #recalc_block_len

Constructor Details

#initialize(options = {}) ⇒ EPB

Returns a new instance of EPB.

Parameters:

  • options (Hash) (defaults to: {})

Options Hash (options):

  • :endian (:little, :big) —

    set block endianness

  • :type (Integer)
  • :block_len (Integer) —

    block total length

  • :interface_id (Integer) —

    specifies the interface this packet comes from

  • :tsh (Integer) —

    timestamp (high nibbles)

  • :tsl (Integer) —

    timestamp (low nibbles)

  • :cap_len (Integer) —

    number of octets captured from the packet

  • :orig_len (Integer) —

    actual length of the packet when it was transmitted on the network

  • :data (::String)
  • :options (::String)
  • :block_len2 (Integer) —

    block total length



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# File 'lib/packetgen/pcapng/epb.rb', line 75

def initialize(options={})
  super
  self.type = options[:type] || PcapNG::EPB_TYPE.to_i
end

Instance Attribute Details

#cap_len ⇒ Integer

32-bit capture length

Returns:

  • (Integer) 


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# File 'lib/packetgen/pcapng/epb.rb', line 49

define_attr_before :block_len2, :cap_len, BinStruct::Int32, default: 0

#data ⇒ BinStruct::String

Returns:

  • (BinStruct::String) 


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# File 'lib/packetgen/pcapng/epb.rb', line 56

define_attr_before :block_len2, :data, BinStruct::String

#endian ⇒ :little, :big

Returns:

  • (:little, :big) 


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# File 'lib/packetgen/pcapng/epb.rb', line 30

def endian
  @endian
end

#interface ⇒ IPB

Returns:

  • (IPB) 


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# File 'lib/packetgen/pcapng/epb.rb', line 32

def interface
  @interface
end

#interface_id ⇒ Integer

32-bit interface ID

Returns:

  • (Integer) 


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# File 'lib/packetgen/pcapng/epb.rb', line 37

define_attr_before :block_len2, :interface_id, BinStruct::Int32, default: 0

#options ⇒ BinStruct::String

Returns:

  • (BinStruct::String) 


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# File 'lib/packetgen/pcapng/epb.rb', line 59

define_attr_before :block_len2, :options, BinStruct::String

#orig_len ⇒ Integer

32-bit original length

Returns:

  • (Integer) 


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# File 'lib/packetgen/pcapng/epb.rb', line 53

define_attr_before :block_len2, :orig_len, BinStruct::Int32, default: 0

#tsh ⇒ Integer

high 32-bit timestamp value

Returns:

  • (Integer) 


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# File 'lib/packetgen/pcapng/epb.rb', line 41

define_attr_before :block_len2, :tsh, BinStruct::Int32, default: 0

#tsl ⇒ Integer

low 32-bit imestamp value

Returns:

  • (Integer) 


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# File 'lib/packetgen/pcapng/epb.rb', line 45

define_attr_before :block_len2, :tsl, BinStruct::Int32, default: 0

Instance Method Details

#read(str_or_io) ⇒ self

Reads a String or a IO to populate the object

Parameters:

  • str_or_io (::String, IO)

Returns:

  • (self) 


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# File 'lib/packetgen/pcapng/epb.rb', line 83

def read(str_or_io)
  io = to_io(str_or_io)
  return self if io.eof?

  i[type block_len interface_id tsh tsl cap_len orig_len].each do |attr|
    self[attr].read(io.read(self[attr].sz))
  end
  self[:data].read(io.read(self.cap_len))
  read_options(io)
  read_blocklen2_and_check(io)

  self
end

#timestamp ⇒ Time

Return timestamp as a Time object

Returns:

  • (Time) 


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# File 'lib/packetgen/pcapng/epb.rb', line 99

def timestamp
  Time.at((self.tsh << 32 | self.tsl) * ts_resol)
end

#timestamp=(time) ⇒ Time

Set timestamp from a Time object

Parameters:

  • time (Time)

Returns:

  • (Time) —

    time



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# File 'lib/packetgen/pcapng/epb.rb', line 106

def timestamp=(time)
  tstamp = (time.to_r / ts_resol).to_i
  self.tsh = (tstamp & 0xffffffff00000000) >> 32
  self.tsl = tstamp & 0xffffffff
  time
end

#to_s ⇒ String

Return the object as a String

Returns:

  • (String) 


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# File 'lib/packetgen/pcapng/epb.rb', line 115

def to_s
  pad_field(:data, :options)
  recalc_block_len
  super
end