Update: Alternate port randomization approaches

[Maxim Konovalov]

On Wed, 29 Dec 2004, 03:02-0600, Mike Silbersack wrote:

> On Sat, 18 Dec 2004, Mike Silbersack wrote:
>
> > There have been a few reports by users of front end web proxies and other
> > systems under FreeBSD that port randomization causes them problems under
> > load.  This seems to be due to a combination of port randomization and
> > rapid connections to the same host causing ports to be recycled before
> > the ISN has advanced past the end of the previous connection, thereby
> > causing the TIME_WAIT socket on the receiving end to ignore the new SYN.
>
> Based on testing done by Igor Sysoev, I've found that my original patch is
> insufficient; even as little as one randomizaion per second can cause problems
> for some users.  As a result, I've created the attached patch (versions for
> both 6.x and 4.x are included).  It implements a relatively simple algorithm:
> Port randomization is turned disable once the connection rate goes above 20
> connections per second, and it is not reenabled until the connection rate
> falls below 20 cps for 5 seconds straight.
>
> This appears to work for Igor, and it seems safe enough to commit before
> 4.11-RC2.  But, if possible, I'd like a few more sets of eyes to doublecheck
> the concept and code; please take a look at it if you have a chance.

Again, it's not clear for me why we don't follow our usual
deveplopment cycle here: commit & test in HEAD and then MFC to STABLE?

-- 
Maxim Konovalov