Class: PacketGen::Header::OSPFv2

Inherits:
Base
  • Object
show all
Defined in:
lib/packetgen/header/ospfv2.rb,
lib/packetgen/header/ospfv2/lsa.rb,
lib/packetgen/header/ospfv2/hello.rb,
lib/packetgen/header/ospfv2/ls_ack.rb,
lib/packetgen/header/ospfv2/ls_update.rb,
lib/packetgen/header/ospfv2/ls_request.rb,
lib/packetgen/header/ospfv2/lsa_header.rb,
lib/packetgen/header/ospfv2/db_description.rb more...

Overview

This class supports OSPFv2 (RFC 2328). An OSPFv2 header has the following format:

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|   Version #   |     Type      |         Packet length         |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                          Router ID                            |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                           Area ID                             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|           Checksum            |             AuType            |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                       Authentication                          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                       Authentication                          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

An OSPFv2 header consists of:

OSPFv2 body

OSPFv2 #body should contain OSPF payload for given #type:

Examples:

Create an OSPFv2 header

# standalone
ospf = PacketGen::Header::OSPFv2.new
# in a packet
pkt = PacketGen.gen('IP').add('OSPFv2')
# make IP header correct for OSPF
pkt.ospfize
# or make it correct with specific destination address
pkt.ospfize(dst: :all_spf_routers)
# access to OSPF header
pkt.ospfv2.class    # => PacketGen::Header::OSPFv2

OSPFv2 attributes

ospf = PacketGen::Header::OSPFv2.new
ospf.version              # => 2
ospf.type = 'LS_ACK'      # or 5
ospf.length = 154
ospf.router_id = 0xc0a80001
ospf.area_id = 1
ospf.checksum = 0xabcd
ospf.au_type = 'NO_AUTH'  # or 0
ospf.authentication = 0

Author:

  • Sylvain Daubert

Since:

  • 2.5.0

Defined Under Namespace

Classes: ArrayOfExternal, ArrayOfLSA, ArrayOfLSR, ArrayOfLink, ArrayOfTosMetric, DbDescription, External, Hello, LSA, LSAASExternal, LSAHeader, LSANetwork, LSARouter, LSAck, LSR, LSRequest, LSUpdate, Link, TosMetric

Constant Summary collapse

IP_PROTOCOL =

IP protocol number for OSPF

Since:

  • 2.5.0

89
TYPES =

OSPF packet types

Since:

  • 2.5.0

{
  'HELLO' => 1,
  'DB_DESCRIPTION' => 2,
  'LS_REQUEST' => 3,
  'LS_UPDATE' => 4,
  'LS_ACK' => 5
}.freeze
AU_TYPES =

Authentication types

Since:

  • 2.5.0

{
  'NO_AUTH' => 0,
  'PASSWORD' => 1,
  'CRYPTO' => 2,
  'CRYPTO_WITH_ESN' => 3
}.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Base

bind, calculate_and_set_length, #header_id, inherited, #initialize, #ip_header, #ll_header

Methods included from PacketGen::Headerable

included, #method_name, #packet, #packet=, #parse?, #protocol_name, #read, #to_s

Constructor Details

This class inherits a constructor from PacketGen::Header::Base

Instance Attribute Details

#area_id ⇒ Integer

32-bit area ID

Returns:

  • (Integer) 

114
 
# File 'lib/packetgen/header/ospfv2.rb', line 114

define_attr :area_id, BinStruct::Int32

#au_type ⇒ Integer

16-bit authentication type. Types are defined in AU_TYPES.

Returns:

  • (Integer) 

122
 
# File 'lib/packetgen/header/ospfv2.rb', line 122

define_attr :au_type, BinStruct::Int16Enum, enum: AU_TYPES

#authentication ⇒ Integer

64-bit authentication data

Returns:

  • (Integer) 

126
 
# File 'lib/packetgen/header/ospfv2.rb', line 126

define_attr :authentication, BinStruct::Int64

#body ⇒ String, Headerable

OSPF body

Returns:


130
 
# File 'lib/packetgen/header/ospfv2.rb', line 130

define_attr :body, BinStruct::String

#checksum ⇒ Integer

16-bit OSPF packet checksum

Returns:

  • (Integer) 

118
 
# File 'lib/packetgen/header/ospfv2.rb', line 118

define_attr :checksum, BinStruct::Int16

#length ⇒ Integer

16-bit OSPF packet length

Returns:

  • (Integer) 

106
 
# File 'lib/packetgen/header/ospfv2.rb', line 106

define_attr :length, BinStruct::Int16

#router_id ⇒ Integer

32-bit router ID

Returns:

  • (Integer) 

110
 
# File 'lib/packetgen/header/ospfv2.rb', line 110

define_attr :router_id, BinStruct::Int32

#type ⇒ Integer

8-bit OSPF packet type. Types are defined in TYPES.

Returns:

  • (Integer) 

102
 
# File 'lib/packetgen/header/ospfv2.rb', line 102

define_attr :type, BinStruct::Int8Enum, enum: TYPES

#version ⇒ Integer

8-bit OSPF version

Returns:

  • (Integer) 

98
 
# File 'lib/packetgen/header/ospfv2.rb', line 98

define_attr :version, BinStruct::Int8, default: 2

Class Method Details

.define_options(hdr) ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

This method returns an undefined value.

Helper class method to define an OSPFv2 options field.

Parameters:

  • hdr (Base) —

    header on which define a OSPFv2 options field

Since:

  • 2.5.0

[View source]

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# File 'lib/packetgen/header/ospfv2.rb', line 162

def self.define_options(hdr)
  hdr.define_bit_attr :options, dn_opt: 1, o_opt: 1, dc_opt: 1, l_opt: 1, n_opt: 1, mc_opt: 1, e_opt: 1, mt_opt: 1
end

Instance Method Details

#added_to_packet(packet) ⇒ void

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Note:

This method is used internally by PacketGen and should not be directly called

This method returns an undefined value.

Add #ospfize method to packet. This method calls #ospfize.

Parameters:

Since:

  • 2.5.0

[View source]

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# File 'lib/packetgen/header/ospfv2.rb', line 172

def added_to_packet(packet)
  ospf_idx = packet.headers.size
  packet.instance_eval "def ospfize(**kwargs) @headers[#{ospf_idx}].ospfize(**kwargs); end" # def ospfize(**kwargs) @headers[2].ospfize(**kwargs); end
end

#calc_checksum ⇒ Integer

Compute checksum and set #checksum attribute

Returns:

  • (Integer)

Since:

  • 2.5.0

[View source]

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# File 'lib/packetgen/header/ospfv2.rb', line 179

def calc_checksum
  # #authentication field is not used in checksum calculation,
  # so force it to 0 before checksumming
  saved_auth = self.authentication
  self.authentication = 0

  sum = IP.sum16(self)
  self.checksum = IP.reduce_checksum(sum)

  # Restore #authentication value
  self.authentication = saved_auth

  self.checksum
end

#calc_length ⇒ Integer

Compute length and set #length attribute

Returns:

  • (Integer)

Since:

  • 2.5.0

[View source]

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# File 'lib/packetgen/header/ospfv2.rb', line 208

def calc_length
  self[:length].value = Base.calculate_and_set_length(self)
end

#human_au_type ⇒ String

Get human-readable AU type

Returns:

  • (String)

Since:

  • 2.5.0

[View source]

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# File 'lib/packetgen/header/ospfv2.rb', line 202

def human_au_type
  self[:au_type].to_human
end

#human_type ⇒ String

Get human-readable type

Returns:

  • (String)

Since:

  • 2.5.0

[View source]

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# File 'lib/packetgen/header/ospfv2.rb', line 196

def human_type
  self[:type].to_human
end

#ospfize(dst: nil) ⇒ void

This method returns an undefined value.

Fixup IP header according to RFC 2328:

  • set TOS field to 0xc0,

  • optionally set destination address,

  • set TTL to 1 if destination is a mcast address.

This method may be called as:

# first way
pkt.ospfv2.ospfize
# second way
pkt.ospfize

Parameters:

  • dst (String, Symbolnil) (defaults to: nil) —

    destination address. May be a dotted IP address (by example ‘224.0.0.5’) or a Symbol (:all_spf_routers or :all_d_routers)

Since:

  • 2.5.0

[View source]

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# File 'lib/packetgen/header/ospfv2.rb', line 225

def ospfize(dst: nil)
  ip = ip_header(self)
  ip.tos = 0xc0
  dst = case dst
        when :all_spf_routers
          '224.0.0.5'
        when :all_d_routers
          '224.0.0.6'
        else
          dst
        end
  ip.dst = dst unless dst.nil?
  ip.ttl = 1 if ip[:dst].mcast?
end