Sha256: 3a135661abc22d8532b15d5da6a957af3e8ebe8a19e95cb03c2ed5adba268eed
Contents?: true
Size: 1.88 KB
Versions: 13
Compression:
Stored size: 1.88 KB
Contents
require 'pio/payload'
require 'pio/type/ip_address'
module Pio
# IP Version 4 Header Format
module IPv4Header
# Internet protocol numbers for ipv4_header.ip_protocol
module ProtocolNumber
ICMP = 1
UDP = 17
end
include Payload
# rubocop:disable MethodLength
# This method smells of :reek:TooManyStatements
def self.included(klass)
def klass.ipv4_header(options = {})
bit4 :ip_version, value: 0x4
bit4 :ip_header_length, initial_value: 0x5
uint8 :ip_type_of_service, initial_value: 0
uint16be :ip_total_length, initial_value: :calculate_ip_length
uint16be :ip_identifier, initial_value: 0
bit3 :ip_flag, initial_value: 0
bit13 :ip_fragment, initial_value: 0
uint8 :ip_ttl, initial_value: 128
uint8 :ip_protocol, initial_value: options[:ip_protocol] || 0
uint16be :ip_header_checksum, initial_value: :calculate_ip_checksum
ip_address :ip_source_address
ip_address :ip_destination_address
string :ip_option, read_length: :ip_option_length
end
end
# rubocop:enable MethodLength
private
def calculate_ip_length
ip_header_length * 4 + ip_payload_binary.length
end
# rubocop:disable AbcSize
def calculate_ip_checksum
sum = [ip_version << 12 | ip_header_length << 8 | ip_type_of_service,
ip_total_length,
ip_identifier,
ip_flag << 13 | ip_fragment,
ip_ttl << 8 | ip_protocol,
ip_source_address >> 16,
ip_source_address & 0xffff,
ip_destination_address >> 16,
ip_destination_address & 0xffff].reduce(:+)
~((sum & 0xffff) + (sum >> 16)) & 0xffff
end
# rubocop:enable AbcSize
def ip_payload_binary
binary_after(:ip_option)
end
def ip_option_length
20 - ip_header_length * 4
end
end
end
Version data entries
13 entries across 13 versions & 1 rubygems