#!/usr/bin/ruby

require 'digest/md5'
require 'socket'

# User setup section
ID = 'someone'	# Your login ID
PASSWD = 'passwd'	# Your password
HOST = 'your-host'	# Your host

# Target Server
SERVER = 'update.minidns.net'
PORT = 9120

# About this program
AGENT_NAME = 'Ruby-Updater'
AGENT_VERSION = '0.1'
AGENT_MODE = 'MD5'

def err? res
	return !(res and !(res =~ /ERR/))
end

soc = TCPSocket.open(SERVER, PORT)
if err?(soc.gets) then raise Exception.new('Fail to open socket!!') end

begin
	soc.write("AGENT #{AGENT_NAME}/#{AGENT_VERSION}")		# send about this program
	if err?(soc.gets) then raise Exception.new($_) end

	case AGENT_MODE
	when 'MD5'
		soc.write("LOGIN #{ID} digest-md5\n")		# send login cmd
		if !(soc.gets =~ /CHALLENGE\s([0-9a-fA-F]*)/) then raise Exception.new($_) end

		md5_passwd = Digest::MD5.digest(PASSWD)
		response = Digest::MD5.hexdigest(md5_passwd + [$1].pack('H*'))
		soc.write("RESPONSE #{response}\n")
		if err?(soc.gets) then raise Exception.new($_) end
	else
		soc.write("LOGIN #{ID} plain\n")		# send login cmd
		soc.write("#{PASSWD}")					# send passwd
		if err?(soc.gets) then raise Exception.new($_) end
	end

	soc.write("A_UPDATE online #{HOST}\n")
	if err?(soc.gets) then raise Exception.new($_) end
rescue
	p $!
ensure
	soc.write("EXIT")
	soc.close
end

exit