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Size: 1.92 KB
Versions: 15
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Stored size: 1.92 KB
Contents
# This file is part of PacketGen
# See https://github.com/sdaubert/packetgen for more informations
# Copyright (C) 2016 Sylvain Daubert <sylvain.daubert@laposte.net>
# This program is published under MIT license.
module PacketGen
module Header
# A ICMP header consists of:
# * a {#type} field ({Types::Int8} type),
# * a {#code} field ({Types::Int8} type),
# * a {#checksum} field ({Types::Int16} type),
# * and a {#body}.
#
# == Create a ICMP header
# # standalone
# icmp = PacketGen::Header::ICMP.new
# # in a packet
# pkt = PacketGen.gen('IP').add('ICMP')
# # access to ICMP header
# pkt.icmp # => PacketGen::Header::ICMP
#
# == ICMP attributes
# icmp.code = 0
# icmp.type = 200
# icmp.checksum = 0x248a
# icmp.body.read 'this is a body'
# @author Sylvain Daubert
class ICMP < Base
# ICMP internet protocol number
IP_PROTOCOL = 1
# @!attribute type
# 8-bit ICMP type
# @return [Integer]
define_field :type, Types::Int8
# @!attribute code
# 8-bit ICMP code
# @return [Integer]
define_field :code, Types::Int8
# @!attribute checksum
# 16-bit ICMP checksum
# @return [Integer]
define_field :checksum, Types::Int16
# @!attribute body
# @return [Types::String,Header::Base]
define_field :body, Types::String
# Compute checksum and set +checksum+ field
# @return [Integer]
def calc_checksum
sum = (type << 8) | code
payload = body.to_s
payload << "\x00" unless payload.size % 2 == 0
payload.unpack('n*').each { |x| sum += x }
while sum > 0xffff do
sum = (sum & 0xffff) + (sum >> 16)
end
sum = ~sum & 0xffff
self[:checksum].value = (sum == 0) ? 0xffff : sum
end
end
self.add_class ICMP
IP.bind_header ICMP, protocol: ICMP::IP_PROTOCOL
end
end
Version data entries
15 entries across 15 versions & 1 rubygems