Re: [PATCH] Pcap recv time for NSE scripts, qscan.nse update

[David Fifield <david () bamsoftware com>]

On Fri, Jul 23, 2010 at 05:45:12AM -0500, Kris Katterjohn wrote:
> On 07/22/2010 09:50 AM, David Fifield wrote:
> > On Wed, Jul 21, 2010 at 08:31:47PM -0500, Kris Katterjohn wrote:
> > > Since the clock_ms() and new pcap time are both using milliseconds, I added a
> > > new TIMEVAL_MSECS() macro to nbase.h for them to share.  This converts a
> > > timeval to milliseconds in unsigned long long format.  This integer type is
> > > used in several other places in the codebase so it should not be a problem,
> > > but do correct me if I'm wrong.  A couple of years ago I fixed a bug in Nmap
> > > by using this type, and I don't recall any difficulty.  clock_ms() was
> > > implemented by casting to lua_Number while converting to msecs, and that's
> > > different than this macro because it's unsigned long long until it's pushed
> > > onto the lua stack as lua_Number.
> >
> > clock_ms was a mistake. It should have been called simply "clock" and
> > returned a floating-point number of seconds. It bothers me that clock_ms
> > deliberately degrades the information it has to provide millisecond
> > precision.
>
> Indeed.  Any plans for creating a new clock() function?  I'm not sure what to
> do with clock_ms() other than mark it deprecated or something equally lame.

A clock function would be welcome. I would just stop using clock_ms.

> It could be cool for a new clock() function to support an optional argument
> for a time specifier like "s" for seconds, "ms" for msecs and (I guess) "us"
> for usecs.  I doubt clock() would need anything larger than "s" like the other
> formats Nmap uses.  Or at least have a stdnse function for keeping the
> converting out of scripts, kinda like parse_timespec().

I think this would be pretty easy:

function clock_ms()
        return clock() * 1000
end
function clock_us()
        return clock() * 1000000
end

The possibilities for what someone would want (ms, us) are limited, so I
think it's a good idea just to define separate functions.

David Fifield
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