Re: [lwip-users] Help regarding packet arrival times.

[K.J. Mansley]

On Thu, 2004-09-30 at 09:33, N V Krishna wrote:
> On Thu, 30 Sep 2004, K.J. Mansley wrote:
> 
> #On Thu, 2004-09-30 at 09:22, N V Krishna wrote:
> #> Hi,
> #> I am trying to validate tcp servers against denial of service attacks by
> #> model checking. To validate this, I want to tally my tool with the
> #> simulated tcp server. I am using simhost + lwip for this.
> #>
> #> For this, I need to know the exact time at which simhost sees a incoming
> #> packet for the first time. Could anyone please give me any pointers? I
> #> need this to get a correct estimate of the exact packet inter arrival time
> #> as seen by the server.
> #
> #What operating system are you using?  Would a packet capture and
> #analysis tool such as ethereal be of any use?
> 
> I am using it on Linux. I am using Spak to send packets. But I want to
> know the timings of packets as seen by simhost.

If nothing external will do, you'll have to alter the source to measure
the time internally.  Measuring time on linux is quite easy though, so
shouldn't be too hard.  e.g. gettimeofday() each time a packet is
received.  There will be some "probe effect" (i.e. the measurements will
take some time, and so may affect the timings you trying to measure)
associated with this though.

Kieran