Ruby で ping を行うプログラムです． 嘘つきました．応答の受信機能はありません．

icmp_echo_message.rb

require 'socket'

class ICMPEchoMessage
  TYPE = 0x08
  CODE = 0x00

  def initialize(id = rand(0..0xffff))
    @id   = id.freeze

    @seq  = 0x0000

    @socket = Socket.open(
      Socket::PF_INET,      # IPv4
      Socket::SOCK_RAW,     # RAW Socket
      Socket::IPPROTO_ICMP  # ICMP
    )
  end

  def send(dest_host, data)
    dest = Socket.sockaddr_in(nil, dest_host)

    @socket.send(packet_data(@seq += 1, data).pack('C*'), 0, dest)
  end

  private

  def packet_data(seq, data, csum = checksum(seq, data))
    [TYPE, CODE] +
      to_bytes(csum, 2) +
      to_bytes(@id, 2) +
      to_bytes(seq, 2) +
      data
  end

  # calcurate checksum
  def checksum(seq, data)
    to_bytes(
      packet_data(seq, data, 0).each_slice(2).inject(0) do |m, i|
        m + to_num((i << 0)[0, 2])
      end
    ).each_slice(2).to_a.reverse.inject(0) do |m, i|
      m + to_num(i.reverse)
    end ^ 0xffff
  end

  # Fixnum to byte array
  def to_bytes(num, size = (num.bit_length / 8.0).ceil)
    Array.new(size) do |i|
      (num >> (i * 8)) & 0xff
    end.reverse
  end

  # Byte array to fixnum
  def to_num(bytes)
    bytes.inject { |m, i| (m << 8) + i }
  end
end

ping.rb

require './icmp_echo_message'

# 送信先ホスト
host  = ARGV[0]

# 送信間隔 [ms]
sleep = ARGV[1] || 1000

# エポック秒を逆順のバイト配列にしたもの
timestamp = -> do
              now = Time.now.to_i
              Array.new(8) { |i| (now >> (i * 8)) & 0xff }
            end.call

ping = ICMPEchoMessage.new
loop do
  ping.send(host, timestamp)
  sleep sleep / 1000.0
end