Class: PacketGen::Header::IKE::SAProposal

Inherits:
Types::Fields show all
Defined in:
lib/packetgen/header/ike/sa.rb

Overview

SA Proposal, as defined in RFC 7296 §3.3.1

                     1                   2                   3
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Last Substruc |   RESERVED    |         Proposal Length       |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Proposal Num  |  Protocol ID  |    SPI Size   |Num  Transforms|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~                        SPI (variable)                         ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                                                               |
~                        <Transforms>                           ~
|                                                               |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Create a proposal

# using protocol name
proposal = PacketGen::Header::IKE::Proposal.new(num: 1, protocol: 'IKE')
# using integer values
proposal = PacketGen::Header::IKE::Proposal.new(num: 1, protocol: 1)

Add transforms to a proposal

# using a Transform object
trans = PacketGen::Header::IKE::Transform.new(type: 'ENCR', id: '3DES')
proposal.transforms << trans
# using a hash
proposal.transforms << { type: 'ENCR', id: '3DES' }

Author:

  • Sylvain Daubert

Since:

  • 2.0.0

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Types::Fields

#[], #[]=, #bits_on, #body=, define_bit_fields_on, define_field, define_field_after, define_field_before, delete_field, fields, #fields, #force_binary, inherited, #inspect, #is_optional?, #is_present?, #offset_of, #optional?, #optional_fields, #present?, remove_bit_fields_on, remove_field, #sz, #to_h, #to_s, update_field

Constructor Details

#initialize(options = {}) ⇒ SAProposal

Returns a new instance of SAProposal.

Since:

  • 2.0.0



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# File 'lib/packetgen/header/ike/sa.rb', line 406

def initialize(options={})
  if options[:spi] && options[:spi_size].nil?
    options[:spi_size] = options[:spi].size
  end
  super
  self[:length].value = sz unless options[:length]
  self.protocol = options[:protocol] if options[:protocol]
end

Instance Attribute Details

#last ⇒ Integer

8-bit last substructure. Specifies whether or not this is the last Proposal Substructure in the SA. This field has a value of 0 if this was the last Proposal Substructure, and a value of 2 if there are more Proposal Substructures.

Returns:

  • (Integer) 


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# File 'lib/packetgen/header/ike/sa.rb', line 364

define_field :last, Types::Int8

#length ⇒ Integer

16-bit proposal length

Returns:

  • (Integer) 


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# File 'lib/packetgen/header/ike/sa.rb', line 372

define_field :length, Types::Int16

#num ⇒ Integer

8-bit proposal number. When a proposal is made, the first proposal in an SA payload MUST be 1, and subsequent proposals MUST be one more than the previous proposal (indicating an OR of the two proposals). When a proposal is accepted, the proposal number in the SA payload MUST match the number on the proposal sent that was accepted.

Returns:

  • (Integer) 


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# File 'lib/packetgen/header/ike/sa.rb', line 381

define_field :num, Types::Int8, default: 1

#num_trans ⇒ Integer

8-bit number of transformations

Returns:

  • (Integer) 


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# File 'lib/packetgen/header/ike/sa.rb', line 395

define_field :num_trans, Types::Int8, default: 0

#protocol ⇒ Integer

8-bit protocol ID. Specify IPsec protocol currently negociated. May 1 (IKE), 2 (AH) or 3 (ESP).

Returns:

  • (Integer) 


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# File 'lib/packetgen/header/ike/sa.rb', line 386

define_field :protocol, Types::Int8

#reserved ⇒ Integer

8-bit reserved field

Returns:

  • (Integer) 


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# File 'lib/packetgen/header/ike/sa.rb', line 368

define_field :reserved, Types::Int8

#spi ⇒ String

the sending entity’s SPI. When the #spi_size field is zero, this field is not present in the proposal.

Returns:

  • (String) 


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# File 'lib/packetgen/header/ike/sa.rb', line 400

define_field :spi, Types::String, builder: ->(h, t) { t.new(length_from: h[:spi_size]) }

#spi_size ⇒ Integer

8-bit SPI size. Give size of SPI field. Set to 0 for an initial IKE SA negotiation, as SPI is obtained from outer header.

Returns:

  • (Integer) 


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# File 'lib/packetgen/header/ike/sa.rb', line 391

define_field :spi_size, Types::Int8, default: 0

#transforms ⇒ Transforms

8-bit set of tranforms for this proposal

Returns:



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# File 'lib/packetgen/header/ike/sa.rb', line 404

define_field :transforms, Transforms, builder: ->(h, t) { t.new(counter: h[:num_trans]) }

Instance Method Details

#calc_length ⇒ Integer

Compute length and set #length field

Returns:

  • (Integer) —

    new length

Since:

  • 2.0.0



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# File 'lib/packetgen/header/ike/sa.rb', line 443

def calc_length
  transforms.each(&:calc_length)
  Base.calculate_and_set_length self
end

#human_protocol ⇒ String

Get protocol name

Returns:

  • (String)

Since:

  • 2.0.0



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# File 'lib/packetgen/header/ike/sa.rb', line 463

def human_protocol
  name = IKE.constants.grep(/PROTO/)
            .detect { |c| IKE.const_get(c) == protocol } || "proto #{protocol}"
  name.to_s.sub(/PROTO_/, '')
end

#last? ⇒ Boolean?

Say if this proposal is the last one (from #last field)

Returns:

  • (Boolean, nil) —

    returns a Boolean when #last has defined value (0 => true, 2 => false), else nil is returned.

Since:

  • 2.0.0



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# File 'lib/packetgen/header/ike/sa.rb', line 472

def last?
  case last
  when 0
    true
  when 2
    false
  end
end

#read(str) ⇒ self

Populate object from a string

Parameters:

  • str (String)

Returns:

  • (self)

Since:

  • 2.0.0



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# File 'lib/packetgen/header/ike/sa.rb', line 433

def read(str)
  super
  hlen = self.class.new.sz + spi_size
  tlen = length - hlen
  transforms.read(str[hlen, tlen])
  self
end

#to_human ⇒ String

Get a human readable string

Returns:

  • (String)

Since:

  • 2.0.0



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# File 'lib/packetgen/header/ike/sa.rb', line 450

def to_human
  str = "##{num} #{human_protocol}".dup
  case spi_size
  when 4
    str << '(spi:0x%08x)' % Types::Int32.new.read(spi).to_i
  when 8
    str << '(spi:0x%016x)' % Types::Int64.new.read(spi).to_i
  end
  str << ":#{transforms.to_human}"
end