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local comm = require "comm"
local datetime = require "datetime"
local shortport = require "shortport"
local stdnse = require "stdnse"
local string = require "string"
local stringaux = require "stringaux"
local nmap = require "nmap"
local os = require "os"
description = [[
Retrieves the day and time from the Time service.
]]
---
-- @output
-- PORT STATE SERVICE
-- 37/tcp open time
-- |_rfc868-time: 2013-10-23T10:33:00
author = "Daniel Miller"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"discovery", "safe", "version"}
portrule = shortport.version_port_or_service(37, "time", {"tcp", "udp"})
action = function(host, port)
local status, result = comm.exchange(host, port, "", {bytes=4})
if status then
local stamp
local width = #result
if width == 4 then
stamp = string.unpack(">I4", result)
port.version.extrainfo = "32 bits"
elseif width == 8 then
stamp = string.unpack(">I4", result)
port.version.extrainfo = "64 bits"
else
stdnse.debug1("Odd response: %s", stringaux.filename_escape(result))
return nil
end
-- RFC 868 epoch is Jan 1, 1900
stamp = stamp - 2208988800
-- Make sure we don't stomp a more-likely service detection.
if port.version.name == "time" then
local recvtime = os.time()
local diff = os.difftime(stamp,recvtime)
if diff < 0 then diff = -diff end
-- confidence decreases by 1 for each year the time is off.
stdnse.debug1("Time difference: %d seconds (%0.2f years)", diff, diff / 31556926)
local confidence = 10 - diff / 31556926
if confidence < 0 then confidence = 0 end
datetime.record_skew(host, stamp, recvtime)
port.version.name_confidence = confidence
nmap.set_port_version(host, port, "hardmatched")
end
return datetime.format_timestamp(stamp)
end
end
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