Class: PacketGen::Header::TCP::Options

Inherits:
Array
  • Object
show all
Defined in:
lib/packetgen/header/tcp/options.rb

Overview

Container for TCP options in TCP header.

Author:

  • Sylvain Daubert

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.option_classes ⇒ Array<Class>

Get PacketGen::Header::TCP::Option subclasses

Returns:

  • (Array<Class>) 


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# File 'lib/packetgen/header/tcp/options.rb', line 11

def self.option_classes
  return @klasses if defined? @klasses
  @klasses = []
  Option.constants.each do |cst|
    next unless cst.to_s.end_with? '_KIND'
    optname = cst.to_s.sub(/_KIND/, '')
    @klasses[Option.const_get(cst)] = TCP.const_get(optname)
  end
  @klasses
end

Instance Method Details

#add(opt, value = nil) ⇒ self

Add a well-known option

Parameters:

  • opt (String) —

    option name

  • value (Object) (defaults to: nil)

Returns:

  • (self)

Raises:

  • (ArgumentError) —

    unknown option



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# File 'lib/packetgen/header/tcp/options.rb', line 55

def add(opt, value=nil)
  raise ArgumentError, "unknown option #{opt}" unless TCP.const_defined?(opt)
  klass = TCP.const_get(opt)
  raise ArgumentError "unknown option #{opt}" unless klass < Option
  option = klass.new(value: value)
  self << option
  self
end

#read(str) ⇒ self

Read TCP header options from a string

Parameters:

  • str (String) —

    binary string

Returns:

  • (self) 


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# File 'lib/packetgen/header/tcp/options.rb', line 25

def read(str)
  clear
  return self if str.nil?
  PacketGen.force_binary str

  i = 0
  klasses = self.class.option_classes
  while i < str.to_s.length
    kind = str[i, 1].unpack('C').first
    this_option = if klasses[kind].nil?
                    Option.new
                  else
                    klasses[kind].new
                  end
    this_option.read str[i, str.size]
    unless this_option.has_length?
      this_option.length = nil
      this_option.value = nil
    end
    self << this_option
    i += this_option.sz
  end
  self
end

#sz ⇒ Integer

Get options size in bytes

Returns:

  • (Integer) 


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# File 'lib/packetgen/header/tcp/options.rb', line 78

def sz
  to_s.length
end

#to_human ⇒ String

Get a human readable string

Returns:



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# File 'lib/packetgen/header/tcp/options.rb', line 72

def to_human
  map(&:to_human).join(', ')
end

#to_s ⇒ String

Get options binary string

Returns:



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# File 'lib/packetgen/header/tcp/options.rb', line 66

def to_s
  map(&:to_s).join
end