Class: PacketGen::Header::Eth

Inherits:

Base

• Object
• Types::Fields
• Base
• PacketGen::Header::Eth

Defined in:

lib/packetgen/header/eth.rb

Overview

An Ethernet header consists of:

• a destination MAC address (MacAddr),

• a source MAC address (MacAddr),

• a #ethertype (Types::Int16),

• and a body (a Types::String or another Header class).

Create a Ethernet header

# standalone
eth = PacketGen::Header::Eth.new
# in a packet
pkt = PacketGen.gen('Eth')
# access to Ethernet header
pkt.eth   # => PacketGen::Header::Eth

Ethernet attributes

eth.dst = "00:01:02:03:04:05"
eth.src        # => "00:01:01:01:01:01"
eth[:src]      # => PacketGen::Header::Eth::MacAddr
eth.ethertype  # => 16-bit Integer
eth.body = "This is a body"

Author:

• Sylvain Daubert

Defined Under Namespace

Classes: MacAddr

Instance Attribute Summary

• #body ⇒ Types::String, Header::Base
• #dst ⇒ MacAddr

  Destination MAC address.

• #ethertype ⇒ Integer

  16-bit integer to determine payload type.

• #src ⇒ MacAddr

  Source MAC address.

Attributes inherited from Base

#packet

Instance Method Summary

• #reply! ⇒ self

  Invert destination and source addresses.

• #to_w(iface) ⇒ void

  send Eth packet on wire.

Methods inherited from Base

#added_to_packet, bind, bind_header, calculate_and_set_length, #header_id, inherited, #initialize, #ip_header, known_headers, #ll_header, #method_name, #parse?, #protocol_name, protocol_name

Methods inherited from Types::Fields

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

Constructor Details

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

Instance Attribute Details

#body ⇒ Types::String, Header::Base

# File 'lib/packetgen/header/eth.rb', line 89

define_field :body, Types::String

#dst ⇒ MacAddr

# File 'lib/packetgen/header/eth.rb', line 80

define_field :dst, MacAddr, default: '00:00:00:00:00:00'

#ethertype ⇒ Integer

# File 'lib/packetgen/header/eth.rb', line 86

define_field :ethertype, Types::Int16, default: 0

#src ⇒ MacAddr

# File 'lib/packetgen/header/eth.rb', line 83

define_field :src, MacAddr, default: '00:00:00:00:00:00'

Instance Method Details

#reply! ⇒ self

Invert destination and source addresses

Since:

• 2.7.0

# File 'lib/packetgen/header/eth.rb', line 103

def reply!
  self[:src], self[:dst] = self[:dst], self[:src]
  self
end

#to_w(iface) ⇒ void

This method returns an undefined value.

send Eth packet on wire.

# File 'lib/packetgen/header/eth.rb', line 94

def to_w(iface)
  pcap = PCAPRUB::Pcap.open_live(iface, PCAP_SNAPLEN, PCAP_PROMISC, PCAP_TIMEOUT)
  pcap.inject self.to_s
  pcap.close
end