Re: TCP timestamp starting value (wa: A strange TCP timestamp problem?)

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Wed, Jul 20, 2016 at 06:43:53PM +0200, Edgar Fuß wrote:
> The starting value of 1 was chosen (over some form or uptime as other OSes do) 
> in order not to leak any information about the system's uptime. The same can 
> be aceived by using something proportional to real time.
> The attached patch implements that (with an arbitrary offset to prevent 
> near-time 32-bit-overflow). The same could be achieved, of course, by simply 
> sampling real time at TCP stack initialization; however, the suggested patch 
> is less intrusive and would allow for run-time tweaking.

Wouldn't a better idea be to compute HASH(cookie,src,dst) + uptime for
some random cookie created at boot time? Essentially, you give each
target a unique monotonic time base, without leaking any data about the
perceived local time.

Joerg